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Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

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  • mardy_marshall
    I ve got an Altair 88-PMC8 EPROM board and am looking for the accompanying WRPROM code. This supplied various burn and load routines for the board. I m not
    Message 1 of 22 , Dec 29, 2007
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      I've got an Altair 88-PMC8 EPROM board and am looking for the accompanying "WRPROM"
      code. This supplied various burn and load routines for the board. I'm not sure if the source
      was ever published. I think that Altair might have just sold a pre-programmed PROM.

      The board itself could hold up to 8 2708 EPROMs and had the ability to program the EPROM's
      on-board. This is what the board looked like:

      http://www.virtualaltair.com/virtualaltair.com/vac_88-PMC8.asp

      The nice thing about this board, besides being able to program on-board, is that 2708's are
      much more plentiful than 1702's, at least for now...

      Thanks,

      -Mardy
    • H.E.Robert Weir-L.V.C.C.
      Mardy, Steve, (Alltare), may have the code, but if the board you have is like the one that just sold on ebay, it was not equipped with write/burn components.
      Message 2 of 22 , Dec 29, 2007
      • 0 Attachment
        Mardy,

        Steve, (Alltare), may have the code, but if the board you have is like the one that just sold on ebay, it was not equipped with write/burn components.  You can tell the difference because the one at the Virtualaltair site does have the burn components installed, like the DC to DC converter module, the black rectangle at the top of the board just to the right of center, if yours doesn't have it, than it's the read only version.

        Just Bob!

        ----- Original Message ----
        From: mardy_marshall <mardy@...>
        To: altaircomputerclub@yahoogroups.com
        Sent: Saturday, December 29, 2007 11:41:04 AM
        Subject: [Altair Computer Club] Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

        I've got an Altair 88-PMC8 EPROM board and am looking for the accompanying "WRPROM"
        code.  This supplied various burn and load routines for the board.  I'm not sure if the source
        was ever published.  I think that Altair might have just sold a pre-programmed PROM.

        The board itself could hold up to 8 2708 EPROMs and had the ability to program the EPROM's
        on-board.  This is what the board looked like:

            http://www.virtualaltair.com/virtualaltair.com/vac_88-PMC8.asp

        The nice thing about this board, besides being able to program on-board, is that 2708's are
        much more plentiful than 1702's, at least for now...

        Thanks,

        -Mardy






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      • Steve
        I don t have the code in any form other than my master WR EPROM chip. If someone here has the ability to make copies of 2708s, I ll be happy to loan it out
        Message 3 of 22 , Dec 29, 2007
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          I don't have the code in any form other than my master WR EPROM
          chip. If someone here has the ability to make copies of 2708s, I'll
          be happy to loan it out long enough to copy. My only request would
          be that you generate a listing that we can make available to the
          other members of the group.

          I have a couple of those DC converters somewhere. It's the main
          component you need to make the read-only PMC-8 into a read/write
          version. If anyone needs one, lemme know. What's a fair price? $10 +
          shipping?

          I wonder if three 9-volt batteries might work as well as the
          converter to blast at least a few chips.

          Steve

          ====================================
          --- In altaircomputerclub@yahoogroups.com, "H.E.Robert Weir-L.V.C.C."
          <ueoguy@...> wrote:
          >
          > Mardy,
          >
          > Steve, (Alltare), may have the code, but if the board you have is
          like the one that just sold on ebay, it was not equipped with
          write/burn components. You can tell the difference because the one
          at the Virtualaltair site does have the burn components installed,
          like the DC to DC converter module, the black rectangle at the top of
          the board just to the right of center, if yours doesn't have it, than
          it's the read only version.
          >
          > Just Bob!
          >
          > ----- Original Message ----
          > From: mardy_marshall <mardy@...>
          > To: altaircomputerclub@yahoogroups.com
          > Sent: Saturday, December 29, 2007 11:41:04 AM
          > Subject: [Altair Computer Club] Looking for "WRPROM" code for
          Altair 88-PMC8 2708 EPROM board
          >
          >
          > I've got an Altair 88-PMC8 EPROM board and am looking for the
          > accompanying "WRPROM"
          > code. This supplied various burn and load routines for the board.
          I'm
          > not sure if the source
          > was ever published. I think that Altair might have just sold a
          > pre-programmed PROM.
          >
          > The board itself could hold up to 8 2708 EPROMs and had the ability
          to
          > program the EPROM's
          > on-board. This is what the board looked like:
          >
          > http://www.virtualaltair.com/virtualaltair.com/vac_88-PMC8.asp
          >
          > The nice thing about this board, besides being able to program
          > on-board, is that 2708's are
          > much more plentiful than 1702's, at least for now...
          >
          > Thanks,
          >
          > -Mardy
          >
          >
          >
          >
          >
          >
          > Yahoo! Groups Links
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          ______________________________________________________________________
          ______________
          > Never miss a thing. Make Yahoo your home page.
          > http://www.yahoo.com/r/hs
          >
        • Grant Stockly
          ... I have the ability to read and write 2708s using a cromemco bytesaver. Grant
          Message 4 of 22 , Dec 29, 2007
          • 0 Attachment
            At 10:43 AM 12/29/2007, you wrote:

            >I don't have the code in any form other than my master WR EPROM
            >chip. If someone here has the ability to make copies of 2708s, I'll
            >be happy to loan it out long enough to copy. My only request would
            >be that you generate a listing that we can make available to the
            >other members of the group.
            >
            >I have a couple of those DC converters somewhere. It's the main
            >component you need to make the read-only PMC-8 into a read/write
            >version. If anyone needs one, lemme know. What's a fair price? $10 +
            >shipping?

            I have the ability to read and write 2708s using a cromemco bytesaver.

            Grant
          • Steve
            The DC converters are all spoken for already. Sorry to those who moved too slow. I m talking to Grant about copying and creating a listing of the WR EPROM.
            Message 5 of 22 , Dec 29, 2007
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              The DC converters are all spoken for already. Sorry to those who
              moved too slow.

              I'm talking to Grant about copying and creating a listing of the WR
              EPROM. I'll post a message when we have results.

              Steve
              =====================================

              --- In altaircomputerclub@yahoogroups.com, Grant Stockly <grant@...>
              wrote:
              >
              > At 10:43 AM 12/29/2007, you wrote:
              >
              > >I don't have the code in any form other than my master WR EPROM
              > >chip. If someone here has the ability to make copies of 2708s, I'll
              > >be happy to loan it out long enough to copy. My only request would
              > >be that you generate a listing that we can make available to the
              > >other members of the group.
              > >
              > >I have a couple of those DC converters somewhere. It's the main
              > >component you need to make the read-only PMC-8 into a read/write
              > >version. If anyone needs one, lemme know. What's a fair price? $10
              +
              > >shipping?
              >
              > I have the ability to read and write 2708s using a cromemco
              bytesaver.
              >
              > Grant
              >
            • H.E.Robert Weir-L.V.C.C.
              Steve, Who was the manufacturer of the converters, do you have the part no. and what the in and out spec s were? I may be able to locate a replacement. Just
              Message 6 of 22 , Dec 30, 2007
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                Steve,

                Who was the manufacturer of the converters, do you have the part no. and what the in and out spec's were?  I may be able to locate a replacement.

                Just Bob!

                ----- Original Message ----
                From: Steve <alltare@...>
                I have a couple of those DC converters somewhere.  It's the main
                component you need to make the read-only PMC-8 into a read/write
                version. If anyone needs one, lemme know.  What's a fair price? $10 +
                shipping?

                I wonder if three 9-volt batteries might work as well as the
                converter to blast at least a few chips.

                Steve

                ====================================
                --- In altaircomputerclub@yahoogroups.com, "H.E.Robert Weir-L.V.C.C."
                <ueoguy@...> wrote:
                >
                > Mardy,
                >
                > Steve, (Alltare), may have the code, but if the board you have is
                like the one that just sold on ebay, it was not equipped with
                write/burn components.  You can tell the difference because the one
                at the Virtualaltair site does have the burn components installed,
                like the DC to DC converter module, the black rectangle at the top of
                the board just to the right of center, if yours doesn't have it, than
                it's the read only version.
                >
                > Just Bob!
                >
                > ----- Original Message ----
                > From: mardy_marshall <mardy@...>
                > To: altaircomputerclub@yahoogroups.com
                > Sent: Saturday, December 29, 2007 11:41:04 AM
                > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                Altair 88-PMC8 2708 EPROM board
                >
                >
                > I've got an Altair 88-PMC8 EPROM board and am looking for the
                >  accompanying "WRPROM"
                > code.  This supplied various burn and load routines for the board. 
                I'm
                >  not sure if the source
                > was ever published.  I think that Altair might have just sold a
                pre-programmed PROM.
                >
                > The board itself could hold up to 8 2708 EPROMs and had the ability
                to
                >  program the EPROM's
                > on-board.  This is what the board looked like:
                >
                >    http://www.virtualaltair.com/virtualaltair.com/vac_88-PMC8.asp
                >
                > The nice thing about this board, besides being able to program
                >  on-board, is that 2708's are
                > much more plentiful than 1702's, at least for now...
                >
                > Thanks,
                >
                > -Mardy
                >
                >
                >
                >
                >

                > Yahoo! Groups Links
                >
                >
                >
                >
                >
                >
                >
                >
                >
                >     
                ______________________________________________________________________
                ______________
                > Never miss a thing.  Make Yahoo
                your home page.
                > http://www.yahoo.com/r/hs
                >





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              • Steve
                Bob- I ll let you know the details when I dig the parts out of storage. Probably Jan 3 or 4. The schematic says +5V in and +26V out (no current specs given).
                Message 7 of 22 , Dec 30, 2007
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                  Bob-
                  I'll let you know the details when I dig the parts out of storage.
                  Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                  current specs given). Oddly, the schematic gives the output as +26V,
                  but after the voltage passes through a jumper wire, they call it
                  +30V.

                  I don't see why it would be difficult to build an equivalent circuit
                  from modern inverter components. You could also use an external bench
                  supply, I suppose, or even use three 9-volt batteries as the source
                  voltage (for a few chips, anyway).

                  steve
                  ============================

                  --- In altaircomputerclub@yahoogroups.com, "H.E.Robert Weir-L.V.C.C."
                  <ueoguy@...> wrote:
                  >
                  > Steve,
                  >
                  > Who was the manufacturer of the converters, do you have the part
                  no. and what the in and out spec's were? I may be able to locate a
                  replacement.
                  >
                  > Just Bob!
                  >
                  > ----- Original Message ----
                  > From: Steve <alltare@...>
                  > I have a couple of those DC converters somewhere. It's the main
                  > component you need to make the read-only PMC-8 into a read/write
                  > version. If anyone needs one, lemme know. What's a fair price? $10
                  +
                  > shipping?
                  >
                  > I wonder if three 9-volt batteries might work as well as the
                  > converter to blast at least a few chips.
                  >
                  > Steve
                  >
                  > ====================================
                  > --- In altaircomputerclub@yahoogroups.com, "H.E.Robert Weir-
                  L.V.C.C."
                  > <ueoguy@> wrote:
                  > >
                  > > Mardy,
                  > >
                  > > Steve, (Alltare), may have the code, but if the board you have is
                  > like the one that just sold on ebay, it was not equipped with
                  > write/burn components. You can tell the difference because the one
                  > at the Virtualaltair site does have the burn components installed,
                  > like the DC to DC converter module, the black rectangle at the top
                  of
                  > the board just to the right of center, if yours doesn't have it,
                  than
                  > it's the read only version.
                  > >
                  > > Just Bob!
                  > >
                  > > ----- Original Message ----
                  > > From: mardy_marshall <mardy@>
                  > > To: altaircomputerclub@yahoogroups.com
                  > > Sent: Saturday, December 29, 2007 11:41:04 AM
                  > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                  > Altair 88-PMC8 2708 EPROM board
                  > >
                  > >
                  > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                  > > accompanying "WRPROM"
                  > > code. This supplied various burn and load routines for the
                  board.
                  > I'm
                  > > not sure if the source
                  > > was ever published. I think that Altair might have just sold a
                  > > pre-programmed PROM.
                  > >
                  > > The board itself could hold up to 8 2708 EPROMs and had the
                  ability
                  > to
                  > > program the EPROM's
                  > > on-board. This is what the board looked like:
                  > >
                  > > http://www.virtualaltair.com/virtualaltair.com/vac_88-PMC8.asp
                  > >
                  > > The nice thing about this board, besides being able to program
                  > > on-board, is that 2708's are
                  > > much more plentiful than 1702's, at least for now...
                  > >
                  > > Thanks,
                  > >
                  > > -Mardy
                  > >
                  > >
                  > >
                  > >
                  > >
                  > >
                  > > Yahoo! Groups Links
                  > >
                  > >
                  > >
                  > >
                  > >
                  > >
                  > >
                  > >
                  > >
                  > >
                  >
                  ______________________________________________________________________
                  > ______________
                  > > Never miss a thing. Make Yahoo your home page.
                  > > http://www.yahoo.com/r/hs
                  > >
                  >
                  >
                  >
                  >
                  >
                  > Yahoo! Groups Links
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  ______________________________________________________________________
                  ______________
                  > Never miss a thing. Make Yahoo your home page.
                  > http://www.yahoo.com/r/hs
                  >
                • Steve
                  I have the modules in hand now, and here s what I know: There is no writing, label, or other markings on the inverters. They re just little black plastic
                  Message 8 of 22 , Jan 5, 2008
                  • 0 Attachment
                    I have the modules in hand now, and here's what I know: There is no
                    writing, label, or other markings on the inverters. They're just
                    little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                    circuitry was placed, then potted with black epoxy.

                    I powered one of them up with 5VDC. The no-load output is 30VDC.
                    With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                    ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                    luck any further, but that ought to be more than enough juice to
                    program a chip.

                    Steve
                    ================================
                    --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@...>
                    wrote:
                    >
                    > Bob-
                    > I'll let you know the details when I dig the parts out of storage.
                    > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                    > current specs given). Oddly, the schematic gives the output as
                    +26V,
                    > but after the voltage passes through a jumper wire, they call it
                    > +30V.
                    >
                    > I don't see why it would be difficult to build an equivalent
                    circuit
                    > from modern inverter components. You could also use an external
                    bench
                    > supply, I suppose, or even use three 9-volt batteries as the source
                    > voltage (for a few chips, anyway).
                    >
                    > steve
                    > ============================
                    >
                    > --- In altaircomputerclub@yahoogroups.com, "H.E.Robert Weir-
                    L.V.C.C."
                    > <ueoguy@> wrote:
                    > >
                    > > Steve,
                    > >
                    > > Who was the manufacturer of the converters, do you have the part
                    > no. and what the in and out spec's were? I may be able to locate a
                    > replacement.
                    > >
                    > > Just Bob!
                    > >
                    > > ----- Original Message ----
                    > > From: Steve <alltare@>
                    > > I have a couple of those DC converters somewhere. It's the main
                    > > component you need to make the read-only PMC-8 into a read/write
                    > > version. If anyone needs one, lemme know. What's a fair price?
                    $10
                    > +
                    > > shipping?
                    > >
                    > > I wonder if three 9-volt batteries might work as well as the
                    > > converter to blast at least a few chips.
                    > >
                    > > Steve
                    > >
                    > > ====================================
                    > > --- In altaircomputerclub@yahoogroups.com, "H.E.Robert Weir-
                    > L.V.C.C."
                    > > <ueoguy@> wrote:
                    > > >
                    > > > Mardy,
                    > > >
                    > > > Steve, (Alltare), may have the code, but if the board you have
                    is
                    > > like the one that just sold on ebay, it was not equipped with
                    > > write/burn components. You can tell the difference because the
                    one
                    > > at the Virtualaltair site does have the burn components
                    installed,
                    > > like the DC to DC converter module, the black rectangle at the
                    top
                    > of
                    > > the board just to the right of center, if yours doesn't have it,
                    > than
                    > > it's the read only version.
                    > > >
                    > > > Just Bob!
                    > > >
                    > > > ----- Original Message ----
                    > > > From: mardy_marshall <mardy@>
                    > > > To: altaircomputerclub@yahoogroups.com
                    > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                    > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                    > > Altair 88-PMC8 2708 EPROM board
                    > > >
                    > > >
                    > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                    > > > accompanying "WRPROM"
                    > > > code. This supplied various burn and load routines for the
                    > board.
                    > > I'm
                    > > > not sure if the source
                    > > > was ever published. I think that Altair might have just sold a
                    > > > pre-programmed PROM.
                    > > >
                    > > > The board itself could hold up to 8 2708 EPROMs and had the
                    > ability
                    > > to
                    > > > program the EPROM's
                    > > > on-board. This is what the board looked like:
                    > > >
                    > > > http://www.virtualaltair.com/virtualaltair.com/vac_88-
                    PMC8.asp
                    > > >
                    > > > The nice thing about this board, besides being able to program
                    > > > on-board, is that 2708's are
                    > > > much more plentiful than 1702's, at least for now...
                    > > >
                    > > > Thanks,
                    > > >
                    > > > -Mardy
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > > Yahoo! Groups Links
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > >
                    >
                    ______________________________________________________________________
                    > > ______________
                    > > > Never miss a thing. Make Yahoo your home page.
                    > > > http://www.yahoo.com/r/hs
                    > > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > > Yahoo! Groups Links
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    >
                    ______________________________________________________________________
                    > ______________
                    > > Never miss a thing. Make Yahoo your home page.
                    > > http://www.yahoo.com/r/hs
                    > >
                    >
                  • H_E_ROBERT_G WEIR_L_V_C_C
                    Steve, Here is a possible replacement, http://www.interq.or.jp/japan/se-inoue/e_ckt27.htm I can t seem to locate any commercially produced DC-DC converter with
                    Message 9 of 22 , Jan 6, 2008
                    • 0 Attachment
                      Steve,

                       Here is a possible replacement, http://www.interq.or.jp/japan/se-inoue/e_ckt27.htm

                      I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                      Maybe somebody else on the list has a better idea?

                      Bob

                      ----- Original Message ----
                      From: Steve <alltare@...>
                      To: altaircomputerclub@yahoogroups.com
                      Sent: Sunday, January 6, 2008 2:01:53 AM
                      Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                      I have the modules in hand now, and here's what I know: There is no
                      writing, label, or other markings on the inverters. They're just
                      little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                      circuitry was placed, then potted with black epoxy.

                      I powered one of them up with 5VDC. The no-load output is 30VDC.
                      With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                      ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                      luck any further, but that ought to be more than enough juice to
                      program a chip.

                      Steve
                      ============ ========= ========= ==
                      --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                      wrote:

                      >
                      > Bob-
                      > I'll let you know the details when I dig the parts out of storage.
                      > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                      > current specs given). Oddly, the schematic gives the output as
                      +26V,
                      > but after the voltage passes through a jumper wire, they call it
                      > +30V.
                      >
                      > I don't see why it would be difficult to build an equivalent
                      circuit
                      > from modern inverter components. You could also use an external
                      bench
                      > supply, I suppose, or even use three 9-volt batteries as the source
                      > voltage (for a few chips, anyway).
                      >
                      > steve
                      > ============ ========= =======
                      >
                      > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                      L.V.C.C."
                      > <ueoguy@> wrote:
                      > >
                      > > Steve,
                      > >
                      > > Who was the manufacturer of the converters, do you have the part
                      > no. and what the in and out spec's were? I may be able to locate a
                      > replacement.
                      > >
                      > > Just Bob!
                      > >
                      > > ----- Original Message ----
                      > > From: Steve <alltare@>
                      > > I have a couple of those DC converters somewhere. It's the main
                      > > component you need to make the read-only PMC-8 into a read/write
                      > > version. If anyone needs one, lemme know. What's a fair price?
                      $10
                      > +
                      > > shipping?
                      > >
                      > > I wonder if three 9-volt batteries might work as well as the
                      > > converter to blast at least a few chips.
                      > >
                      > > Steve
                      > >
                      > > ============ ========= ========= ======
                      > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                      > L.V.C.C."
                      > > <ueoguy@> wrote:
                      > > >
                      > > > Mardy,
                      > > >
                      > > > Steve, (Alltare), may have the code, but if the board you have
                      is
                      > > like the one that just sold on ebay, it was not equipped with
                      > > write/burn components. You can tell the difference because the
                      one
                      > > at the Virtualaltair site does have the burn components
                      installed,
                      > > like the DC to DC converter module, the black rectangle at the
                      top
                      > of
                      > > the board just to the right of center, if yours doesn't have it,
                      > than
                      > > it's the read only version.
                      > > >
                      > > > Just Bob!
                      > > >
                      > > > ----- Original Message ----
                      > > > From: mardy_marshall <mardy@>
                      > > > To: altaircomputerclub@ yahoogroups. com
                      > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                      > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                      > > Altair 88-PMC8 2708 EPROM board
                      > > >
                      > > >
                      > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                      > > > accompanying "WRPROM"
                      > > > code. This supplied various burn and load routines for the
                      > board.
                      > > I'm
                      > > > not sure if the source
                      > > > was ever published. I think that Altair might have just sold a
                      > > > pre-programmed PROM.
                      > > >
                      > > > The board itself could hold up to 8 2708 EPROMs and had the
                      > ability
                      > > to
                      > > > program the EPROM's
                      > > > on-board. This is what the board looked like:
                      > > >
                      > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                      PMC8.asp
                      > > >
                      > > > The nice thing about this board, besides being able to program
                      > > > on-board, is that 2708's are
                      > > > much more plentiful than 1702's, at least for now...
                      > > >
                      > > > Thanks,
                      > > >
                      > > > -Mardy
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > > Yahoo! Groups Links
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > >
                      >
                      ____________ _________ _________ _________ _________ _________ _
                      > > ____________ __
                      > > > Never miss a thing. Make Yahoo your home page.
                      > > > http://www.yahoo. com/r/hs
                      > > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > > Yahoo! Groups Links
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      >
                      ____________ _________ _________ _________ _________ _________ _
                      > ____________ __
                      > > Never miss a thing. Make Yahoo your home page.
                      > > http://www.yahoo. com/r/hs
                      > >
                      >




                      Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
                    • Derek J. Lassen
                      How about http://www.allelectronics.com/cgi-bin/item/DC-32/200/DC-DC_CONVERTER_.html
                      Message 10 of 22 , Jan 6, 2008
                      • 0 Attachment
                        How about
                        http://www.allelectronics.com/cgi-bin/item/DC-32/200/DC-DC_CONVERTER_.html

                        At 03:07 AM 1/6/2008 -0800, you wrote:

                        Steve,

                         Here is a possible replacement, http://www.interq.or.jp/japan/se-inoue/e_ckt27.htm

                        I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                        Maybe somebody else on the list has a better idea?

                        Bob

                        ----- Original Message ----
                        From: Steve <alltare@...>
                        To: altaircomputerclub@yahoogroups.com
                        Sent: Sunday, January 6, 2008 2:01:53 AM
                        Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                        I have the modules in hand now, and here's what I know: There is no
                        writing, label, or other markings on the inverters. They're just
                        little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                        circuitry was placed, then potted with black epoxy.

                        I powered one of them up with 5VDC. The no-load output is 30VDC.
                        With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                        ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                        luck any further, but that ought to be more than enough juice to
                        program a chip.

                        Steve
                        ============ ========= ========= ==
                        --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                        wrote:
                        >
                        > Bob-
                        > I'll let you know the details when I dig the parts out of storage.
                        > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                        > current specs given). Oddly, the schematic gives the output as
                        +26V,
                        > but after the voltage passes through a jumper wire, they call it
                        > +30V.
                        >
                        > I don't see why it would be difficult to build an equivalent
                        circuit
                        > from modern inverter components. You could also use an external
                        bench
                        > supply, I suppose, or even use three 9-volt batteries as the source
                        > voltage (for a few chips, anyway).
                        >
                        > steve
                        > ============ ========= =======
                        >
                        > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                        L.V.C.C."
                        > <ueoguy@> wrote:
                        > >
                        > > Steve,
                        > >
                        > > Who was the manufacturer of the converters, do you have the part
                        > no. and what the in and out spec's were? I may be able to locate a
                        > replacement.
                        > >
                        > > Just Bob!
                        > >
                        > > ----- Original Message ----
                        > > From: Steve <alltare@>
                        > > I have a couple of those DC converters somewhere. It's the main
                        > > component you need to make the read-only PMC-8 into a read/write
                        > > version. If anyone needs one, lemme know. What's a fair price?
                        $10
                        > +
                        > > shipping?
                        > >
                        > > I wonder if three 9-volt batteries might work as well as the
                        > > converter to blast at least a few chips.
                        > >
                        > > Steve
                        > >
                        > > ============ ========= ========= ======
                        > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                        > L.V.C.C."
                        > > <ueoguy@> wrote:
                        > > >
                        > > > Mardy,
                        > > >
                        > > > Steve, (Alltare), may have the code, but if the board you have
                        is
                        > > like the one that just sold on ebay, it was not equipped with
                        > > write/burn components. You can tell the difference because the
                        one
                        > > at the Virtualaltair site does have the burn components
                        installed,
                        > > like the DC to DC converter module, the black rectangle at the
                        top
                        > of
                        > > the board just to the right of center, if yours doesn't have it,
                        > than
                        > > it's the read only version.
                        > > >
                        > > > Just Bob!
                        > > >
                        > > > ----- Original Message ----
                        > > > From: mardy_marshall <mardy@>
                        > > > To: altaircomputerclub@ yahoogroups. com
                        > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                        > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                        > > Altair 88-PMC8 2708 EPROM board
                        > > >
                        > > >
                        > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                        > > > accompanying "WRPROM"
                        > > > code. This supplied various burn and load routines for the
                        > board.
                        > > I'm
                        > > > not sure if the source
                        > > > was ever published. I think that Altair might have just sold a
                        > > > pre-programmed PROM.
                        > > >
                        > > > The board itself could hold up to 8 2708 EPROMs and had the
                        > ability
                        > > to
                        > > > program the EPROM's
                        > > > on-board. This is what the board looked like:
                        > > >
                        > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                        PMC8.asp
                        > > >
                        > > > The nice thing about this board, besides being able to program
                        > > > on-board, is that 2708's are
                        > > > much more plentiful than 1702's, at least for now...
                        > > >
                        > > > Thanks,
                        > > >
                        > > > -Mardy
                        > > >
                        > > >
                        > > >
                        > > >
                        > > >
                      • H_E_ROBERT_G WEIR_L_V_C_C
                        Hi Derek, Not a bad idea, the only problem, is the 2708 s need a programming supply, (and this I got from another site, and may not be accurate), of a minimum
                        Message 11 of 22 , Jan 6, 2008
                        • 0 Attachment
                          Hi Derek,
                          Not a bad idea, the only problem, is the 2708's need a programming supply, (and this I got from another site, and may not be accurate), of a minimum +27.3VDC to work reliably.  I did see a similar circuit described, and looks physically almost identical, I think the same PCB was used, but it used maybe a positive logic version of the custom round chip. See....

                          http://www.interq.or.jp/japan/se-inoue/e_ckt28.htm

                          But the module and chip, are long out of production !

                          Bob
                          ----- Original Message ----
                          From: Derek J. Lassen <xl198CV56@...>
                          To: altaircomputerclub@yahoogroups.com
                          Sent: Sunday, January 6, 2008 6:34:55 AM
                          Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                          How about
                          http://www.allelect ronics.com/ cgi-bin/item/ DC-32/200/ DC-DC_CONVERTER_ .html

                          At 03:07 AM 1/6/2008 -0800, you wrote:

                          Steve,

                           Here is a possible replacement, http://www.interq. or.jp/japan/ se-inoue/ e_ckt27.htm

                          I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                          Maybe somebody else on the list has a better idea?

                          Bob

                          ----- Original Message ----
                          From: Steve <alltare@yahoo. com>
                          To: altaircomputerclub@ yahoogroups. com
                          Sent: Sunday, January 6, 2008 2:01:53 AM
                          Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                          I have the modules in hand now, and here's what I know: There is no
                          writing, label, or other markings on the inverters. They're just
                          little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                          circuitry was placed, then potted with black epoxy.

                          I powered one of them up with 5VDC. The no-load output is 30VDC.
                          With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                          ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                          luck any further, but that ought to be more than enough juice to
                          program a chip.

                          Steve
                          ============ ========= ========= ==
                          --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                          wrote:
                          >
                          > Bob-
                          > I'll let you know the details when I dig the parts out of storage.
                          > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                          > current specs given). Oddly, the schematic gives the output as
                          +26V,
                          > but after the voltage passes through a jumper wire, they call it
                          > +30V.
                          >
                          > I don't see why it would be difficult to build an equivalent
                          circuit
                          > from modern inverter components. You could also use an external
                          bench
                          > supply, I suppose, or even use three 9-volt batteries as the source
                          > voltage (for a few chips, anyway).
                          >
                          > steve
                          > ============ ========= =======
                          >
                          > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                          L.V.C.C."
                          > <ueoguy@> wrote:
                          > >
                          > > Steve,
                          > >
                          > > Who was the manufacturer of the converters, do you have the part
                          > no. and what the in and out spec's were? I may be able to locate a
                          > replacement.
                          > >
                          > > Just Bob!
                          > >
                          > > ----- Original Message ----
                          > > From: Steve <alltare@>
                          > > I have a couple of those DC converters somewhere. It's the main
                          > > component you need to make the read-only PMC-8 into a read/write
                          > > version. If anyone needs one, lemme know. What's a fair price?
                          $10
                          > +
                          > > shipping?
                          > >
                          > > I wonder if three 9-volt batteries might work as well as the
                          > > converter to blast at least a few chips.
                          > >
                          > > Steve
                          > >
                          > > ============ ========= ========= ======
                          > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                          > L.V.C.C."
                          > > <ueoguy@> wrote:
                          > > >
                          > > > Mardy,
                          > > >
                          > > > Steve, (Alltare), may have the code, but if the board you have
                          is
                          > > like the one that just sold on ebay, it was not equipped with
                          > > write/burn components. You can tell the difference because the
                          one
                          > > at the Virtualaltair site does have the burn components
                          installed,
                          > > like the DC to DC converter module, the black rectangle at the
                          top
                          > of
                          > > the board just to the right of center, if yours doesn't have it,
                          > than
                          > > it's the read only version.
                          > > >
                          > > > Just Bob!
                          > > >
                          > > > ----- Original Message ----
                          > > > From: mardy_marshall <mardy@>
                          > > > To: altaircomputerclub@ yahoogroups. com
                          > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                          > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                          > > Altair 88-PMC8 2708 EPROM board
                          > > >
                          > > >
                          > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                          > > > accompanying "WRPROM"
                          > > > code. This supplied various burn and load routines for the
                          > board.
                          > > I'm
                          > > > not sure if the source
                          > > > was ever published. I think that Altair might have just sold a
                          > > > pre-programmed PROM.
                          > > >
                          > > > The board itself could hold up to 8 2708 EPROMs and had the
                          > ability
                          > > to
                          > > > program the EPROM's
                          > > > on-board. This is what the board looked like:
                          > > >
                          > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                          PMC8.asp
                          > > >
                          > > > The nice thing about this board, besides being able to program
                          > > > on-board, is that 2708's are
                          > > > much more plentiful than 1702's, at least for now...
                          > > >
                          > > > Thanks,
                          > > >
                          > > > -Mardy
                          > > >
                          > > >
                          > > >
                          > > >
                          > > >




                          Never miss a thing. Make Yahoo your homepage.
                        • Steve
                          Maxim makes a lot of inverter chips of the charge-pump and switcher varieties. Many of them could probably be used as the heart of a suitable circuit.
                          Message 12 of 22 , Jan 6, 2008
                          • 0 Attachment
                            Maxim makes a lot of inverter chips of the charge-pump and switcher
                            varieties. Many of them could probably be used as the heart of a
                            suitable circuit. Maxim's DC-DC chips can be found here:
                            http://www.maxim-ic.com/products/power/dc_dc_switchers/

                            I think that one important criterion would be that the no-load
                            voltage not rise above the max allowable write voltage of the 2708
                            (~30V?). When first applied, you don't want to have the voltage so
                            high that it will damage the 2708.

                            Derek, a problem with the circuit that you suggested is that, besides
                            the 26 Volt output being possibly a little too low, it's also of the
                            wrong polarity. If the input and output didn't have the same common
                            ground, that wouldn't be a problem, but since the -5V input is
                            internally connected to the +26V output, it just won't work. The
                            PMC8 circuit board requires that both negative terminals be grounded.

                            Steve
                            =================================================

                            --- In altaircomputerclub@yahoogroups.com, "Derek J. Lassen"
                            <xl198CV56@...> wrote:
                            >
                            > How about
                            > http://www.allelectronics.com/cgi-bin/item/DC-32/200/DC-
                            DC_CONVERTER_.html
                            >
                            > At 03:07 AM 1/6/2008 -0800, you wrote:
                            >
                            > >Steve,
                            > >
                            > > Here is a possible replacement,
                            > > <http://www.interq.or.jp/japan/se-
                            inoue/e_ckt27.htm>http://www.interq.or.jp/japan/se-inoue/e_ckt27.htm
                            > >
                            > >I can't seem to locate any commercially produced DC-DC converter
                            > >with a 5V input and an output greater than 12-16VDC. The only
                            > >drawback is the current produced, very small, and I am not sure
                            what
                            > >the current draw for programming the 2708 actually is?
                            > >
                            > >Maybe somebody else on the list has a better idea?
                            > >
                            > >Bob
                            > >
                            > >----- Original Message ----
                            > >From: Steve <alltare@...>
                            > >To: altaircomputerclub@yahoogroups.com
                            > >Sent: Sunday, January 6, 2008 2:01:53 AM
                            > >Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for
                            > >Altair 88-PMC8 2708 EPROM board
                            > >
                            > >I have the modules in hand now, and here's what I know: There is no
                            > >writing, label, or other markings on the inverters. They're just
                            > >little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which
                            the
                            > >circuitry was placed, then potted with black epoxy.
                            > >
                            > >I powered one of them up with 5VDC. The no-load output is 30VDC.
                            > >With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                            > >ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                            > >luck any further, but that ought to be more than enough juice to
                            > >program a chip.
                            > >
                            > >Steve
                            > >============ ========= ========= ==
                            > >--- In
                            > ><mailto:altaircomputerclub%40yahoogroups.com>altaircomputerclub@
                            > >yahoogroups. com, "Steve" <alltare@ >
                            > >wrote:
                            > > >
                            > > > Bob-
                            > > > I'll let you know the details when I dig the parts out of
                            storage.
                            > > > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                            > > > current specs given). Oddly, the schematic gives the output as
                            > >+26V,
                            > > > but after the voltage passes through a jumper wire, they call it
                            > > > +30V.
                            > > >
                            > > > I don't see why it would be difficult to build an equivalent
                            > >circuit
                            > > > from modern inverter components. You could also use an external
                            > >bench
                            > > > supply, I suppose, or even use three 9-volt batteries as the
                            source
                            > > > voltage (for a few chips, anyway).
                            > > >
                            > > > steve
                            > > > ============ ========= =======
                            > > >
                            > > > --- In
                            > > <mailto:altaircomputerclub%40yahoogroups.com>altaircomputerclub@
                            > > yahoogroups. com, "H.E.Robert Weir-
                            > >L.V.C.C."
                            > > > <ueoguy@> wrote:
                            > > > >
                            > > > > Steve,
                            > > > >
                            > > > > Who was the manufacturer of the converters, do you have the
                            part
                            > > > no. and what the in and out spec's were? I may be able to
                            locate a
                            > > > replacement.
                            > > > >
                            > > > > Just Bob!
                            > > > >
                            > > > > ----- Original Message ----
                            > > > > From: Steve <alltare@>
                            > > > > I have a couple of those DC converters somewhere. It's the
                            main
                            > > > > component you need to make the read-only PMC-8 into a
                            read/write
                            > > > > version. If anyone needs one, lemme know. What's a fair price?
                            > >$10
                            > > > +
                            > > > > shipping?
                            > > > >
                            > > > > I wonder if three 9-volt batteries might work as well as the
                            > > > > converter to blast at least a few chips.
                            > > > >
                            > > > > Steve
                            > > > >
                            > > > > ============ ========= ========= ======
                            > > > > --- In
                            > > <mailto:altaircomputerclub%40yahoogroups.com>altaircomputerclub@
                            > > yahoogroups. com, "H.E.Robert Weir-
                            > > > L.V.C.C."
                            > > > > <ueoguy@> wrote:
                            > > > > >
                            > > > > > Mardy,
                            > > > > >
                            > > > > > Steve, (Alltare), may have the code, but if the board you
                            have
                            > >is
                            > > > > like the one that just sold on ebay, it was not equipped with
                            > > > > write/burn components. You can tell the difference because the
                            > >one
                            > > > > at the Virtualaltair site does have the burn components
                            > >installed,
                            > > > > like the DC to DC converter module, the black rectangle at the
                            > >top
                            > > > of
                            > > > > the board just to the right of center, if yours doesn't have
                            it,
                            > > > than
                            > > > > it's the read only version.
                            > > > > >
                            > > > > > Just Bob!
                            > > > > >
                            > > > > > ----- Original Message ----
                            > > > > > From: mardy_marshall <mardy@>
                            > > > > > To:
                            > > <mailto:altaircomputerclub%40yahoogroups.com>altaircomputerclub@
                            > > yahoogroups. com
                            > > > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                            > > > > > Subject: [Altair Computer Club] Looking for "WRPROM" code
                            for
                            > > > > Altair 88-PMC8 2708 EPROM board
                            > > > > >
                            > > > > >
                            > > > > > I've got an Altair 88-PMC8 EPROM board and am looking for
                            the
                            > > > > > accompanying "WRPROM"
                            > > > > > code. This supplied various burn and load routines for the
                            > > > board.
                            > > > > I'm
                            > > > > > not sure if the source
                            > > > > > was ever published. I think that Altair might have just
                            sold a
                            > > > > > pre-programmed PROM.
                            > > > > >
                            > > > > > The board itself could hold up to 8 2708 EPROMs and had the
                            > > > ability
                            > > > > to
                            > > > > > program the EPROM's
                            > > > > > on-board. This is what the board looked like:
                            > > > > >
                            > > > > >
                            > > <http://www.virtualaltair.com/virtualaltair.com/vac_88-
                            >http://www.virtuala
                            > > ltair.com/ virtualaltair. com/vac_88-
                            > >PMC8.asp
                            > > > > >
                            > > > > > The nice thing about this board, besides being able to
                            program
                            > > > > > on-board, is that 2708's are
                            > > > > > much more plentiful than 1702's, at least for now...
                            > > > > >
                            > > > > > Thanks,
                            > > > > >
                            > > > > > -Mardy
                            > > > > >
                            > > > > >
                            > > > > >
                            > > > > >
                            > > > > >
                            >
                          • Dan Roganti
                            I took a look at the datasheets I have on the 2708, between TI, INTEL and NTE. This is what they show Program Pulse (pin 18) Voltage min.= 25v, nom.= 26v max.
                            Message 13 of 22 , Jan 6, 2008
                            • 0 Attachment

                              I took a look at the datasheets I have on the 2708, between TI, INTEL and NTE.
                              This is what they show

                              Program Pulse (pin 18)
                              Voltage
                                  min.= 25v,
                                  nom.= 26v
                                  max. = 27v
                              Input current = 40ma

                              I don't know where you got the 27.3V minimum program pulse voltage, but I didn't see it.
                              Judging from the spec chart on that link with the DC-DC converter,
                              even though it can output as much as 45ma under load, the output drops below 25v.
                              It wouldn't have enough output voltage/current to satisfy the specs on the 2708.
                              As mentioned before, the input current is low enough to let only 9V batteries in series be connected.
                              The schematics I have for a 2708 programmer (manual style) are wired this way.

                              =Dan



                              H_E_ROBERT_G WEIR_L_V_C_C wrote:
                              Hi Derek,
                              Not a bad idea, the only problem, is the 2708's need a programming supply, (and this I got from another site, and may not be accurate), of a minimum +27.3VDC to work reliably.  I did see a similar circuit described, and looks physically almost identical, I think the same PCB was used, but it used maybe a positive logic version of the custom round chip. See....

                              http://www.interq. or.jp/japan/ se-inoue/ e_ckt28.htm

                              But the module and chip, are long out of production !

                              Bob
                              ----- Original Message ----
                              From: Derek J. Lassen <xl198CV56@dc. rr.com>
                              To: altaircomputerclub@ yahoogroups. com
                              Sent: Sunday, January 6, 2008 6:34:55 AM
                              Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                              How about
                              http://www.allelect ronics.com/ cgi-bin/item/ DC-32/200/ DC-DC_CONVERTER_ .html

                              At 03:07 AM 1/6/2008 -0800, you wrote:

                              Steve,

                               Here is a possible replacement, http://www.interq. or.jp/japan/ se-inoue/ e_ckt27.htm

                              I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                              Maybe somebody else on the list has a better idea?

                              Bob

                              ----- Original Message ----
                              From: Steve <alltare@yahoo. com>
                              To: altaircomputerclub@ yahoogroups. com
                              Sent: Sunday, January 6, 2008 2:01:53 AM
                              Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                              I have the modules in hand now, and here's what I know: There is no
                              writing, label, or other markings on the inverters. They're just
                              little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                              circuitry was placed, then potted with black epoxy.

                              I powered one of them up with 5VDC. The no-load output is 30VDC.
                              With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                              ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                              luck any further, but that ought to be more than enough juice to
                              program a chip.

                              Steve
                              ============ ========= ========= ==
                              --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                              wrote:
                              >
                              > Bob-
                              > I'll let you know the details when I dig the parts out of storage.
                              > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                              > current specs given). Oddly, the schematic gives the output as
                              +26V,
                              > but after the voltage passes through a jumper wire, they call it
                              > +30V.
                              >
                              > I don't see why it would be difficult to build an equivalent
                              circuit
                              > from modern inverter components. You could also use an external
                              bench
                              > supply, I suppose, or even use three 9-volt batteries as the source
                              > voltage (for a few chips, anyway).
                              >
                              > steve
                              > ============ ========= =======
                              >
                              > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                              L.V.C.C."
                              > <ueoguy@> wrote:
                              > >
                              > > Steve,
                              > >
                              > > Who was the manufacturer of the converters, do you have the part
                              > no. and what the in and out spec's were? I may be able to locate a
                              > replacement.
                              > >
                              > > Just Bob!
                              > >
                              > > ----- Original Message ----
                              > > From: Steve <alltare@>
                              > > I have a couple of those DC converters somewhere. It's the main
                              > > component you need to make the read-only PMC-8 into a read/write
                              > > version. If anyone needs one, lemme know. What's a fair price?
                              $10
                              > +
                              > > shipping?
                              > >
                              > > I wonder if three 9-volt batteries might work as well as the
                              > > converter to blast at least a few chips.
                              > >
                              > > Steve
                              > >
                              > > ============ ========= ========= ======
                              > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                              > L.V.C.C."
                              > > <ueoguy@> wrote:
                              > > >
                              > > > Mardy,
                              > > >
                              > > > Steve, (Alltare), may have the code, but if the board you have
                              is
                              > > like the one that just sold on ebay, it was not equipped with
                              > > write/burn components. You can tell the difference because the
                              one
                              > > at the Virtualaltair site does have the burn components
                              installed,
                              > > like the DC to DC converter module, the black rectangle at the
                              top
                              > of
                              > > the board just to the right of center, if yours doesn't have it,
                              > than
                              > > it's the read only version.
                              > > >
                              > > > Just Bob!
                              > > >
                              > > > ----- Original Message ----
                              > > > From: mardy_marshall <mardy@>
                              > > > To: altaircomputerclub@ yahoogroups. com
                              > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                              > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                              > > Altair 88-PMC8 2708 EPROM board
                              > > >
                              > > >
                              > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                              > > > accompanying "WRPROM"
                              > > > code. This supplied various burn and load routines for the
                              > board.
                              > > I'm
                              > > > not sure if the source
                              > > > was ever published. I think that Altair might have just sold a
                              > > > pre-programmed PROM.
                              > > >
                              > > > The board itself could hold up to 8 2708 EPROMs and had the
                              > ability
                              > > to
                              > > > program the EPROM's
                              > > > on-board. This is what the board looked like:
                              > > >
                              > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                              PMC8.asp
                              > > >
                              > > > The nice thing about this board, besides being able to program
                              > > > on-board, is that 2708's are
                              > > > much more plentiful than 1702's, at least for now...
                              > > >
                              > > > Thanks,
                              > > >
                              > > > -Mardy
                              > > >
                              > > >
                              > > >
                              > > >
                              > > >



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                            • Dan Roganti
                              yep, that DC-DC converter from allelectronics has the wrong polarity. And the one from the japan link is the one that is too weak. =Dan Steve wrote: Maxim
                              Message 14 of 22 , Jan 6, 2008
                              • 0 Attachment

                                yep, that DC-DC converter from allelectronics has the wrong polarity.
                                And the one from the japan link is the one that is too weak.

                                =Dan

                                Steve wrote:

                                Maxim makes a lot of inverter chips of the charge-pump and switcher
                                varieties. Many of them could probably be used as the heart of a
                                suitable circuit. Maxim's DC-DC chips can be found here:
                                http://www.maxim- ic.com/products/ power/dc_ dc_switchers/

                                I think that one important criterion would be that the no-load
                                voltage not rise above the max allowable write voltage of the 2708
                                (~30V?). When first applied, you don't want to have the voltage so
                                high that it will damage the 2708.

                                Derek, a problem with the circuit that you suggested is that, besides
                                the 26 Volt output being possibly a little too low, it's also of the
                                wrong polarity. If the input and output didn't have the same common
                                ground, that wouldn't be a problem, but since the -5V input is
                                internally connected to the +26V output, it just won't work. The
                                PMC8 circuit board requires that both negative terminals be grounded.

                                Steve
                                ============ ========= ========= ========= ========= =

                                --- In altaircomputerclub@ yahoogroups. com, "Derek J. Lassen"
                                <xl198CV56@. ..> wrote:
                                >
                                > How about
                                > http://www.allelect ronics.com/ cgi-bin/item/ DC-32/200/ DC-
                                DC_CONVERTER_ .html
                                >
                                > At 03:07 AM 1/6/2008 -0800, you wrote:
                                >
                                > >Steve,
                                > >
                                > > Here is a possible replacement,
                                > > <http://www.interq. or.jp/japan/ se-
                                inoue/e_ckt27. htm>http://www.interq. or.jp/japan/ se-inoue/ e_ckt27.htm
                                > >
                                > >I can't seem to locate any commercially produced DC-DC converter
                                > >with a 5V input and an output greater than 12-16VDC. The only
                                > >drawback is the current produced, very small, and I am not sure
                                what
                                > >the current draw for programming the 2708 actually is?
                                > >
                                > >Maybe somebody else on the list has a better idea?
                                > >
                                > >Bob
                                > >
                                > >----- Original Message ----
                                > >From: Steve <alltare@... >
                                > >To: altaircomputerclub@ yahoogroups. com
                                > >Sent: Sunday, January 6, 2008 2:01:53 AM
                                > >Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for
                                > >Altair 88-PMC8 2708 EPROM board
                                > >
                                > >I have the modules in hand now, and here's what I know: There is no
                                > >writing, label, or other markings on the inverters. They're just
                                > >little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which
                                the
                                > >circuitry was placed, then potted with black epoxy.
                                > >
                                > >I powered one of them up with 5VDC. The no-load output is 30VDC.
                                > >With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                                > >ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                                > >luck any further, but that ought to be more than enough juice to
                                > >program a chip.
                                > >
                                > >Steve
                                > >=========== = ========= ========= ==
                                > >--- In
                                > ><mailto:altaircomp uterclub% 40yahoogroups. com>altaircomput erclub@
                                > >yahoogroups. com, "Steve" <alltare@ >
                                > >wrote:
                                > > >
                                > > > Bob-
                                > > > I'll let you know the details when I dig the parts out of
                                storage.
                                > > > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                                > > > current specs given). Oddly, the schematic gives the output as
                                > >+26V,
                                > > > but after the voltage passes through a jumper wire, they call it
                                > > > +30V.
                                > > >
                                > > > I don't see why it would be difficult to build an equivalent
                                > >circuit
                                > > > from modern inverter components. You could also use an external
                                > >bench
                                > > > supply, I suppose, or even use three 9-volt batteries as the
                                source
                                > > > voltage (for a few chips, anyway).
                                > > >
                                > > > steve
                                > > > ============ ========= =======
                                > > >
                                > > > --- In
                                > > <mailto:altaircompu terclub%40yahoog roups.com> altaircomputercl ub@
                                > > yahoogroups. com, "H.E.Robert Weir-
                                > >L.V.C.C."
                                > > > <ueoguy@> wrote:
                                > > > >
                                > > > > Steve,
                                > > > >
                                > > > > Who was the manufacturer of the converters, do you have the
                                part
                                > > > no. and what the in and out spec's were? I may be able to
                                locate a
                                > > > replacement.
                                > > > >
                                > > > > Just Bob!
                                > > > >
                                > > > > ----- Original Message ----
                                > > > > From: Steve <alltare@>
                                > > > > I have a couple of those DC converters somewhere. It's the
                                main
                                > > > > component you need to make the read-only PMC-8 into a
                                read/write
                                > > > > version. If anyone needs one, lemme know. What's a fair price?
                                > >$10
                                > > > +
                                > > > > shipping?
                                > > > >
                                > > > > I wonder if three 9-volt batteries might work as well as the
                                > > > > converter to blast at least a few chips.
                                > > > >
                                > > > > Steve
                                > > > >
                                > > > > ============ ========= ========= ======
                                > > > > --- In
                                > > <mailto:altaircompu terclub%40yahoog roups.com> altaircomputercl ub@
                                > > yahoogroups. com, "H.E.Robert Weir-
                                > > > L.V.C.C."
                                > > > > <ueoguy@> wrote:
                                > > > > >
                                > > > > > Mardy,
                                > > > > >
                                > > > > > Steve, (Alltare), may have the code, but if the board you
                                have
                                > >is
                                > > > > like the one that just sold on ebay, it was not equipped with
                                > > > > write/burn components. You can tell the difference because the
                                > >one
                                > > > > at the Virtualaltair site does have the burn components
                                > >installed,
                                > > > > like the DC to DC converter module, the black rectangle at the
                                > >top
                                > > > of
                                > > > > the board just to the right of center, if yours doesn't have
                                it,
                                > > > than
                                > > > > it's the read only version.
                                > > > > >
                                > > > > > Just Bob!
                                > > > > >
                                > > > > > ----- Original Message ----
                                > > > > > From: mardy_marshall <mardy@>
                                > > > > > To:
                                > > <mailto:altaircompu terclub%40yahoog roups.com> altaircomputercl ub@
                                > > yahoogroups. com
                                > > > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                                > > > > > Subject: [Altair Computer Club] Looking for "WRPROM" code
                                for
                                > > > > Altair 88-PMC8 2708 EPROM board
                                > > > > >
                                > > > > >
                                > > > > > I've got an Altair 88-PMC8 EPROM board and am looking for
                                the
                                > > > > > accompanying "WRPROM"
                                > > > > > code. This supplied various burn and load routines for the
                                > > > board.
                                > > > > I'm
                                > > > > > not sure if the source
                                > > > > > was ever published. I think that Altair might have just
                                sold a
                                > > > > > pre-programmed PROM.
                                > > > > >
                                > > > > > The board itself could hold up to 8 2708 EPROMs and had the
                                > > > ability
                                > > > > to
                                > > > > > program the EPROM's
                                > > > > > on-board. This is what the board looked like:
                                > > > > >
                                > > > > >
                                > > <http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                                >http://www.virtuala
                                > > ltair.com/ virtualaltair. com/vac_88-
                                > >PMC8.asp
                                > > > > >
                                > > > > > The nice thing about this board, besides being able to
                                program
                                > > > > > on-board, is that 2708's are
                                > > > > > much more plentiful than 1702's, at least for now...
                                > > > > >
                                > > > > > Thanks,
                                > > > > >
                                > > > > > -Mardy
                                > > > > >
                                > > > > >
                                > > > > >
                                > > > > >
                                > > > > >
                                >


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                              • H_E_ROBERT_G WEIR_L_V_C_C
                                Dan, Your finding certainly agree with Steve s testing of the original module. The 27.3 figure I gleaned from a SYM-1 user group site that had
                                Message 15 of 22 , Jan 6, 2008
                                • 0 Attachment
                                  Dan,

                                  Your finding certainly agree with Steve's testing of the original module.  The 27.3 figure I gleaned from a SYM-1 user group site that had plans/schematics for a home brew programmer that plugged into the afore mentioned CPU.  the author was rather adamant about that particular fact, the only reason I mentioned it.  Here's the site....

                                  http://www.6502.org/users/dallas/SYM/SYM%20Projects/2708%20EPROM%20Burner/Description.htm


                                  And here is a site with a programmer designed around the SWTP 6800...

                                  http://www.swtpc.com/mholley/MicroWorks/B09_Index.htm

                                  Bob

                                  ----- Original Message ----
                                  From: Dan Roganti <ragooman@...>
                                  To: altaircomputerclub@yahoogroups.com
                                  Sent: Sunday, January 6, 2008 1:43:20 PM
                                  Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board


                                  I took a look at the datasheets I have on the 2708, between TI, INTEL and NTE.
                                  This is what they show

                                  Program Pulse (pin 18)
                                  Voltage
                                      min.= 25v,
                                      nom.= 26v
                                      max. = 27v
                                  Input current = 40ma

                                  I don't know where you got the 27.3V minimum program pulse voltage, but I didn't see it.




                                  H_E_ROBERT_G WEIR_L_V_C_C wrote:

                                  Hi Derek,
                                  Not a bad idea, the only problem, is the 2708's need a programming supply, (and this I got from another site, and may not be accurate), of a minimum +27.3VDC to work reliably.  I did see a similar circuit described, and looks physically almost identical, I think the same PCB was used, but it used maybe a positive logic version of the custom round chip. See....

                                  http://www.interq. or.jp/japan/ se-inoue/ e_ckt28.htm

                                  But the module and chip, are long out of production !

                                  Bob
                                  ----- Original Message ----
                                  From: Derek J. Lassen <xl198CV56@dc. rr.com>
                                  To: altaircomputerclub@ yahoogroups. com
                                  Sent: Sunday, January 6, 2008 6:34:55 AM
                                  Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                                  How about
                                  http://www.allelect ronics.com/ cgi-bin/item/ DC-32/200/ DC-DC_CONVERTER_ .html

                                  At 03:07 AM 1/6/2008 -0800, you wrote:

                                  Steve,

                                   Here is a possible replacement, http://www.interq. or.jp/japan/ se-inoue/ e_ckt27.htm

                                  I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                                  Maybe somebody else on the list has a better idea?

                                  Bob

                                  ----- Original Message ----
                                  From: Steve <alltare@yahoo. com>
                                  To: altaircomputerclub@ yahoogroups. com
                                  Sent: Sunday, January 6, 2008 2:01:53 AM
                                  Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                                  I have the modules in hand now, and here's what I know: There is no
                                  writing, label, or other markings on the inverters. They're just
                                  little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                                  circuitry was placed, then potted with black epoxy.

                                  I powered one of them up with 5VDC. The no-load output is 30VDC.
                                  With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                                  ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                                  luck any further, but that ought to be more than enough juice to
                                  program a chip.

                                  Steve
                                  ============ ========= ========= ==
                                  --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                                  wrote:
                                  >
                                  > Bob-
                                  > I'll let you know the details when I dig the parts out of storage.
                                  > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                                  > current specs given). Oddly, the schematic gives the output as
                                  +26V,
                                  > but after the voltage passes through a jumper wire, they call it
                                  > +30V.
                                  >
                                  > I don't see why it would be difficult to build an equivalent
                                  circuit
                                  > from modern inverter components. You could also use an external
                                  bench
                                  > supply, I suppose, or even use three 9-volt batteries as the source
                                  > voltage (for a few chips, anyway).
                                  >
                                  > steve
                                  > ============ ========= =======
                                  >
                                  > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                                  L.V.C.C."
                                  > <ueoguy@> wrote:
                                  > >
                                  > > Steve,
                                  > >
                                  > > Who was the manufacturer of the converters, do you have the part
                                  > no. and what the in and out spec's were? I may be able to locate a
                                  > replacement.
                                  > >
                                  > > Just Bob!
                                  > >
                                  > > ----- Original Message ----
                                  > > From: Steve <alltare@>
                                  > > I have a couple of those DC converters somewhere. It's the main
                                  > > component you need to make the read-only PMC-8 into a read/write
                                  > > version. If anyone needs one, lemme know. What's a fair price?
                                  $10
                                  > +
                                  > > shipping?
                                  > >
                                  > > I wonder if three 9-volt batteries might work as well as the
                                  > > converter to blast at least a few chips.
                                  > >
                                  > > Steve
                                  > >
                                  > > ============ ========= ========= ======
                                  > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                                  > L.V.C.C."
                                  > > <ueoguy@> wrote:
                                  > > >
                                  > > > Mardy,
                                  > > >
                                  > > > Steve, (Alltare), may have the code, but if the board you have
                                  is
                                  > > like the one that just sold on ebay, it was not equipped with
                                  > > write/burn components. You can tell the difference because the
                                  one
                                  > > at the Virtualaltair site does have the burn components
                                  installed,
                                  > > like the DC to DC converter module, the black rectangle at the
                                  top
                                  > of
                                  > > the board just to the right of center, if yours doesn't have it,
                                  > than
                                  > > it's the read only version.
                                  > > >
                                  > > > Just Bob!
                                  > > >
                                  > > > ----- Original Message ----
                                  > > > From: mardy_marshall <mardy@>
                                  > > > To: altaircomputerclub@ yahoogroups. com
                                  > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                                  > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                                  > > Altair 88-PMC8 2708 EPROM board
                                  > > >
                                  > > >
                                  > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                                  > > > accompanying "WRPROM"
                                  > > > code. This supplied various burn and load routines for the
                                  > board.
                                  > > I'm
                                  > > > not sure if the source
                                  > > > was ever published. I think that Altair might have just sold a
                                  > > > pre-programmed PROM.
                                  > > >
                                  > > > The board itself could hold up to 8 2708 EPROMs and had the
                                  > ability
                                  > > to
                                  > > > program the EPROM's
                                  > > > on-board. This is what the board looked like:
                                  > > >
                                  > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                                  PMC8.asp
                                  > > >
                                  > > > The nice thing about this board, besides being able to program
                                  > > > on-board, is that 2708's are
                                  > > > much more plentiful than 1702's, at least for now...
                                  > > >
                                  > > > Thanks,
                                  > > >
                                  > > > -Mardy
                                  > > >
                                  > > >
                                  > > >
                                  > > >
                                  > > >



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                                • Dan Roganti
                                  Bob, From looking at the links there, I noticed why it mentions 27.3v in the one schematic at the 6502 website. This happens to be the requirement for an
                                  Message 16 of 22 , Jan 6, 2008
                                  • 0 Attachment
                                    Bob,

                                    From looking at the links there, I noticed why it mentions 27.3v in the one schematic at the 6502 website. This happens to be the requirement for an external power supply. Which is usually alittle higher to compensate for any voltage drop through the switching circuit in the programmer. In this case, they have 2 driver transistors to switch the programming voltage to the eprom. The biploar transistors will consume some extra power for switching, before it reaches the program pin on the eprom.

                                    In the swtpc link, there's something very interesting in that circuit. They use a charge pump to generate the 26v from the 12v regulator using a 555 timer. I checked online, there's some good references for a 555 Timer charge pump. I've seen this done before with a transformer on the output of the 555 to generate much higher voltages. This can be a good alternative and it could be made to fit in the same space on the 88-PMC8 card (sine it doesn't need a xmfr) . I was going to try to breadboard this and test it.

                                    =Dan


                                    H_E_ROBERT_G WEIR_L_V_C_C wrote:
                                    Dan,

                                    Your finding certainly agree with Steve's testing of the original module.  The 27.3 figure I gleaned from a SYM-1 user group site that had plans/schematics for a home brew programmer that plugged into the afore mentioned CPU.  the author was rather adamant about that particular fact, the only reason I mentioned it.  Here's the site....

                                    http://www.6502. org/users/ dallas/SYM/ SYM%20Projects/ 2708%20EPROM% 20Burner/ Description. htm


                                    And here is a site with a programmer designed around the SWTP 6800...

                                    http://www.swtpc. com/mholley/ MiroWorks/ B09_Index. htm

                                    Bob

                                    ----- Original Message ----
                                    From: Dan Roganti <ragooman@comcast. net>
                                    To: altaircomputerclub@ yahoogroups. com
                                    Sent: Sunday, January 6, 2008 1:43:20 PM
                                    Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board


                                    I took a look at the datasheets I have on the 2708, between TI, INTEL and NTE.
                                    This is what they show

                                    Program Pulse (pin 18)
                                    Voltage
                                        min.= 25v,
                                        nom.= 26v
                                        max. = 27v
                                    Input current = 40ma

                                    I don't know where you got the 27.3V minimum program pulse voltage, but I didn't see it.




                                    H_E_ROBERT_G WEIR_L_V_C_C wrote:

                                    Hi Derek,
                                    Not a bad idea, the only problem, is the 2708's need a programming supply, (and this I got from another site, and may not be accurate), of a minimum +27.3VDC to work reliably.  I did see a similar circuit described, and looks physically almost identical, I think the same PCB was used, but it used maybe a positive logic version of the custom round chip. See....

                                    http://www.interq. or.jp/japan/ se-inoue/ e_ckt28.htm

                                    But the module and chip, are long out of production !

                                    Bob
                                    ----- Original Message ----
                                    From: Derek J. Lassen <xl198CV56@dc. rr.com>
                                    To: altaircomputerclub@ yahoogroups. com
                                    Sent: Sunday, January 6, 2008 6:34:55 AM
                                    Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                                    How about
                                    http://www.allelect ronics.com/ cgi-bin/item/ DC-32/200/ DC-DC_CONVERTER_ .html

                                    At 03:07 AM 1/6/2008 -0800, you wrote:

                                    Steve,

                                     Here is a possible replacement, http://www.interq. or.jp/japan/ se-inoue/ e_ckt27.htm

                                    I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                                    Maybe somebody else on the list has a better idea?

                                    Bob

                                    ----- Original Message ----
                                    From: Steve <alltare@yahoo. com>
                                    To: altaircomputerclub@ yahoogroups. com
                                    Sent: Sunday, January 6, 2008 2:01:53 AM
                                    Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                                    I have the modules in hand now, and here's what I know: There is no
                                    writing, label, or other markings on the inverters. They're just
                                    little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                                    circuitry was placed, then potted with black epoxy.

                                    I powered one of them up with 5VDC. The no-load output is 30VDC.
                                    With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                                    ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                                    luck any further, but that ought to be more than enough juice to
                                    program a chip.

                                    Steve
                                    ============ ========= ========= ==
                                    --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                                    wrote:
                                    >
                                    > Bob-
                                    > I'll let you know the details when I dig the parts out of storage.
                                    > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                                    > current specs given). Oddly, the schematic gives the output as
                                    +26V,
                                    > but after the voltage passes through a jumper wire, they call it
                                    > +30V.
                                    >
                                    > I don't see why it would be difficult to build an equivalent
                                    circuit
                                    > from modern inverter components. You could also use an external
                                    bench
                                    > supply, I suppose, or even use three 9-volt batteries as the source
                                    > voltage (for a few chips, anyway).
                                    >
                                    > steve
                                    > ============ ========= =======
                                    >
                                    > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                                    L.V.C.C."
                                    > <ueoguy@> wrote:
                                    > >
                                    > > Steve,
                                    > >
                                    > > Who was the manufacturer of the converters, do you have the part
                                    > no. and what the in and out spec's were? I may be able to locate a
                                    > replacement.
                                    > >
                                    > > Just Bob!
                                    > >
                                    > > ----- Original Message ----
                                    > > From: Steve <alltare@>
                                    > > I have a couple of those DC converters somewhere. It's the main
                                    > > component you need to make the read-only PMC-8 into a read/write
                                    > > version. If anyone needs one, lemme know. What's a fair price?
                                    $10
                                    > +
                                    > > shipping?
                                    > >
                                    > > I wonder if three 9-volt batteries might work as well as the
                                    > > converter to blast at least a few chips.
                                    > >
                                    > > Steve
                                    > >
                                    > > ============ ========= ========= ======
                                    > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                                    > L.V.C.C."
                                    > > <ueoguy@> wrote:
                                    > > >
                                    > > > Mardy,
                                    > > >
                                    > > > Steve, (Alltare), may have the code, but if the board you have
                                    is
                                    > > like the one that just sold on ebay, it was not equipped with
                                    > > write/burn components. You can tell the difference because the
                                    one
                                    > > at the Virtualaltair site does have the burn components
                                    installed,
                                    > > like the DC to DC converter module, the black rectangle at the
                                    top
                                    > of
                                    > > the board just to the right of center, if yours doesn't have it,
                                    > than
                                    > > it's the read only version.
                                    > > >
                                    > > > Just Bob!
                                    > > >
                                    > > > ----- Original Message ----
                                    > > > From: mardy_marshall <mardy@>
                                    > > > To: altaircomputerclub@ yahoogroups. com
                                    > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                                    > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                                    > > Altair 88-PMC8 2708 EPROM board
                                    > > >
                                    > > >
                                    > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                                    > > > accompanying "WRPROM"
                                    > > > code. This supplied various burn and load routines for the
                                    > board.
                                    > > I'm
                                    > > > not sure if the source
                                    > > > was ever published. I think that Altair might have just sold a
                                    > > > pre-programmed PROM.
                                    > > >
                                    > > > The board itself could hold up to 8 2708 EPROMs and had the
                                    > ability
                                    > > to
                                    > > > program the EPROM's
                                    > > > on-board. This is what the board looked like:
                                    > > >
                                    > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                                    PMC8.asp
                                    > > >
                                    > > > The nice thing about this board, besides being able to program
                                    > > > on-board, is that 2708's are
                                    > > > much more plentiful than 1702's, at least for now...
                                    > > >
                                    > > > Thanks,
                                    > > >
                                    > > > -Mardy
                                    > > >
                                    > > >
                                    > > >
                                    > > >
                                    > > >



                                    Never miss a thing. Make Yahoo your homepage.

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                                  • Dan Roganti
                                    I built a 27V DC-DC converter on a breadboard. All the components can fit in a small space, even on the PMC8 card I took the circuit from the other programmer
                                    Message 17 of 22 , Jan 16, 2008
                                    • 0 Attachment

                                      I built a 27V DC-DC converter on a breadboard.
                                      All the components can fit in a small space, even on the PMC8 card
                                      I took the circuit from the other programmer that Bob found on the swtpc website
                                      I made some modifications to the circuit to make it more robust.
                                      That original circuit required an extra neg.5v regulator which took up more space.
                                      The output is even more stable and regulated, it's capable of sourcing 50ma output.
                                      This is more than enough for the program pin on the 2708.
                                      I was going to use this to make a benchtop 2708 programmer.(and 1702A-with more voltage)

                                      =Dan


                                      Dan Roganti wrote:

                                      Bob,

                                      >From looking at the links there, I noticed why it mentions 27.3v in the one schematic at the 6502 website. This happens to be the requirement for an external power supply. Which is usually alittle higher to compensate for any voltage drop through the switching circuit in the programmer. In this case, they have 2 driver transistors to switch the programming voltage to the eprom. The biploar transistors will consume some extra power for switching, before it reaches the program pin on the eprom.

                                      In the swtpc link, there's something very interesting in that circuit. They use a charge pump to generate the 26v from the 12v regulator using a 555 timer. I checked online, there's some good references for a 555 Timer charge pump. I've seen this done before with a transformer on the output of the 555 to generate much higher voltages. This can be a good alternative and it could be made to fit in the same space on the 88-PMC8 card (sine it doesn't need a xmfr) . I was going to try to breadboard this and test it.

                                      =Dan


                                      H_E_ROBERT_G WEIR_L_V_C_C wrote:

                                      Dan,

                                      Your finding certainly agree with Steve's testing of the original module.  The 27.3 figure I gleaned from a SYM-1 user group site that had plans/schematics for a home brew programmer that plugged into the afore mentioned CPU.  the author was rather adamant about that particular fact, the only reason I mentioned it.  Here's the site....

                                      http://www.6502. org/users/ dallas/SYM/ SYM%20Projects/ 2708%20EPROM% 20Burner/ Description. htm


                                      And here is a site with a programmer designed around the SWTP 6800...

                                      http://www.swtpc. com/mholley/ MiroWorks/ B09_Index. htm

                                      Bob

                                      ----- Original Message ----
                                      From: Dan Roganti <ragooman@comcast. net>
                                      To: altaircomputerclub@ yahoogroups. com
                                      Sent: Sunday, January 6, 2008 1:43:20 PM
                                      Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board


                                      I took a look at the datasheets I have on the 2708, between TI, INTEL and NTE.
                                      This is what they show

                                      Program Pulse (pin 18)
                                      Voltage
                                          min.= 25v,
                                          nom.= 26v
                                          max. = 27v
                                      Input current = 40ma

                                      I don't know where you got the 27.3V minimum program pulse voltage, but I didn't see it.




                                      H_E_ROBERT_G WEIR_L_V_C_C wrote:

                                      Hi Derek,
                                      Not a bad idea, the only problem, is the 2708's need a programming supply, (and this I got from another site, and may not be accurate), of a minimum +27.3VDC to work reliably.  I did see a similar circuit described, and looks physically almost identical, I think the same PCB was used, but it used maybe a positive logic version of the custom round chip. See....

                                      http://www.interq. or.jp/japan/ se-inoue/ e_ckt28.htm

                                      But the module and chip, are long out of production !

                                      Bob
                                      ----- Original Message ----
                                      From: Derek J. Lassen <xl198CV56@dc. rr.com>
                                      To: altaircomputerclub@ yahoogroups. com
                                      Sent: Sunday, January 6, 2008 6:34:55 AM
                                      Subject: Re: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                                      How about
                                      http://www.allelect ronics.com/ cgi-bin/item/ DC-32/200/ DC-DC_CONVERTER_ .html

                                      At 03:07 AM 1/6/2008 -0800, you wrote:

                                      Steve,

                                       Here is a possible replacement, http://www.interq. or.jp/japan/ se-inoue/ e_ckt27.htm

                                      I can't seem to locate any commercially produced DC-DC converter with a 5V input and an output greater than 12-16VDC.  The only drawback is the current produced, very small, and I am not sure what the current draw for programming the 2708 actually is?

                                      Maybe somebody else on the list has a better idea?

                                      Bob

                                      ----- Original Message ----
                                      From: Steve <alltare@yahoo. com>
                                      To: altaircomputerclub@ yahoogroups. com
                                      Sent: Sunday, January 6, 2008 2:01:53 AM
                                      Subject: [Altair Computer Club] Re: Looking for "WRPROM" code for Altair 88-PMC8 2708 EPROM board

                                      I have the modules in hand now, and here's what I know: There is no
                                      writing, label, or other markings on the inverters. They're just
                                      little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                                      circuitry was placed, then potted with black epoxy.

                                      I powered one of them up with 5VDC. The no-load output is 30VDC.
                                      With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                                      ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                                      luck any further, but that ought to be more than enough juice to
                                      program a chip.

                                      Steve
                                      ============ ========= ========= ==
                                      --- In altaircomputerclub@ yahoogroups. com, "Steve" <alltare@... >
                                      wrote:
                                      >
                                      > Bob-
                                      > I'll let you know the details when I dig the parts out of storage.
                                      > Probably Jan 3 or 4. The schematic says +5V in and +26V out (no
                                      > current specs given). Oddly, the schematic gives the output as
                                      +26V,
                                      > but after the voltage passes through a jumper wire, they call it
                                      > +30V.
                                      >
                                      > I don't see why it would be difficult to build an equivalent
                                      circuit
                                      > from modern inverter components. You could also use an external
                                      bench
                                      > supply, I suppose, or even use three 9-volt batteries as the source
                                      > voltage (for a few chips, anyway).
                                      >
                                      > steve
                                      > ============ ========= =======
                                      >
                                      > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                                      L.V.C.C."
                                      > <ueoguy@> wrote:
                                      > >
                                      > > Steve,
                                      > >
                                      > > Who was the manufacturer of the converters, do you have the part
                                      > no. and what the in and out spec's were? I may be able to locate a
                                      > replacement.
                                      > >
                                      > > Just Bob!
                                      > >
                                      > > ----- Original Message ----
                                      > > From: Steve <alltare@>
                                      > > I have a couple of those DC converters somewhere. It's the main
                                      > > component you need to make the read-only PMC-8 into a read/write
                                      > > version. If anyone needs one, lemme know. What's a fair price?
                                      $10
                                      > +
                                      > > shipping?
                                      > >
                                      > > I wonder if three 9-volt batteries might work as well as the
                                      > > converter to blast at least a few chips.
                                      > >
                                      > > Steve
                                      > >
                                      > > ============ ========= ========= ======
                                      > > --- In altaircomputerclub@ yahoogroups. com, "H.E.Robert Weir-
                                      > L.V.C.C."
                                      > > <ueoguy@> wrote:
                                      > > >
                                      > > > Mardy,
                                      > > >
                                      > > > Steve, (Alltare), may have the code, but if the board you have
                                      is
                                      > > like the one that just sold on ebay, it was not equipped with
                                      > > write/burn components. You can tell the difference because the
                                      one
                                      > > at the Virtualaltair site does have the burn components
                                      installed,
                                      > > like the DC to DC converter module, the black rectangle at the
                                      top
                                      > of
                                      > > the board just to the right of center, if yours doesn't have it,
                                      > than
                                      > > it's the read only version.
                                      > > >
                                      > > > Just Bob!
                                      > > >
                                      > > > ----- Original Message ----
                                      > > > From: mardy_marshall <mardy@>
                                      > > > To: altaircomputerclub@ yahoogroups. com
                                      > > > Sent: Saturday, December 29, 2007 11:41:04 AM
                                      > > > Subject: [Altair Computer Club] Looking for "WRPROM" code for
                                      > > Altair 88-PMC8 2708 EPROM board
                                      > > >
                                      > > >
                                      > > > I've got an Altair 88-PMC8 EPROM board and am looking for the
                                      > > > accompanying "WRPROM"
                                      > > > code. This supplied various burn and load routines for the
                                      > board.
                                      > > I'm
                                      > > > not sure if the source
                                      > > > was ever published. I think that Altair might have just sold a
                                      > > > pre-programmed PROM.
                                      > > >
                                      > > > The board itself could hold up to 8 2708 EPROMs and had the
                                      > ability
                                      > > to
                                      > > > program the EPROM's
                                      > > > on-board. This is what the board looked like:
                                      > > >
                                      > > > http://www.virtuala ltair.com/ virtualaltair. com/vac_88-
                                      PMC8.asp
                                      > > >
                                      > > > The nice thing about this board, besides being able to program
                                      > > > on-board, is that 2708's are
                                      > > > much more plentiful than 1702's, at least for now...
                                      > > >
                                      > > > Thanks,
                                      > > >
                                      > > > -Mardy
                                      > > >
                                      > > >
                                      > > >
                                      > > >
                                      > > >



                                      Never miss a thing. Make Yahoo your homepage.


                                    • h_e_robert_g
                                      Hey Dan, Sounds very promising! I hope you can share the schematic an layout with the group, or at least offer them for sale? I ve been still looking around,
                                      Message 18 of 22 , Jan 17, 2008
                                      • 0 Attachment
                                        Hey Dan,

                                        Sounds very promising! I hope you can share the schematic an layout
                                        with the group, or at least offer them for sale?

                                        I've been still looking around, for additional info on programing 1702's
                                        and branching out to include 2708's, and I found a board from Vector
                                        Graphic Inc., that had a very simple 26v generator, I will upload the
                                        PDF and take a look at section 3.4, and the schematics. In a nut shell,
                                        the last socket on their board is the programing socket, all yo have to
                                        do, is insert a prom, operate an on board switch, which enables the 26V
                                        supply to the socket, then just write the data to the prom address
                                        range, 256 times, and it's done! Apparently that number of writes
                                        insures that it is programmed. Take a look!

                                        Bob
                                      • Dan Roganti
                                        I can, I was planning to make available a blank pcb or a complete board. I could take the dimensions such that it can fit within the footprint of the DC
                                        Message 19 of 22 , Jan 17, 2008
                                        • 0 Attachment

                                          I can, I was planning to make available a blank pcb or a complete board. I could take the dimensions such that it can fit within the footprint of the DC converter on the PMC8 card. It can then always fit inside my benchtop programmer.

                                          Now after taking a look at that Vector Graphic card, it turns out to be a much simpler design, it has a lot fewer parts to deal with--it saves even more space. I have the power supply equations from the datasheet plugged into an excel sheet here so I can try different values. So I was going to get these parts soon and breadboard this too.

                                          =Dan



                                          h_e_robert_g wrote:

                                          Hey Dan,

                                          Sounds very promising! I hope you can share the schematic an layout
                                          with the group, or at least offer them for sale?

                                          I've been still looking around, for additional info on programing 1702's
                                          and branching out to include 2708's, and I found a board from Vector
                                          Graphic Inc., that had a very simple 26v generator, I will upload the
                                          PDF and take a look at section 3.4, and the schematics. In a nut shell,
                                          the last socket on their board is the programing socket, all yo have to
                                          do, is insert a prom, operate an on board switch, which enables the 26V
                                          supply to the socket, then just write the data to the prom address
                                          range, 256 times, and it's done! Apparently that number of writes
                                          insures that it is programmed. Take a look!

                                          Bob


                                          No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.6/1230 - Release Date: 1/17/2008 4:59 PM
                                        • Dan Roganti
                                          Would someone have the pin spacing of this module on the PMC8 card ? I don t seem to have the correct manual to determine this. The dimensions from the
                                          Message 20 of 22 , Jan 27, 2008
                                          • 0 Attachment


                                            Would someone have the pin spacing of this module on the PMC8 card ?
                                            I don't seem to have the correct manual to determine this.

                                            The dimensions from the previous post below is already possible to reproduce.
                                            I can prepare a board which can fit in the same space as the old DC converter on the PMC8 card
                                            I'm also preparing a pcb to fit in my benchtop eprom programmer, which includes other hardware.

                                            This is using the switcher part from the Vector Graphic card that Bob mentioned.
                                            I have all the switcher equations entered in excel to let me calculate the necessary values for each part.
                                            This will be a lot more reliable than using the 555 timer method, so I'm ditching that one.
                                            My parts are coming in the mail, so I can test it soon, I'll keep you posted.

                                            =Dan


                                            Steve wrote:

                                            I have the modules in hand now, and here's what I know: There is no
                                            writing, label, or other markings on the inverters. They're just
                                            little black plastic 5-sided boxes, 1.75 x 1 x 0.56", into which the
                                            circuitry was placed, then potted with black epoxy.

                                            I powered one of them up with 5VDC. The no-load output is 30VDC.
                                            With a 1Kohm load (~28mA), the output dropped to 28VDC. With a 390
                                            ohm load (~68mA), the output dropped to 26.5VDC. I didn't push my
                                            luck any further, but that ought to be more than enough juice to
                                            program a chip.

                                            Steve


                                          • Steve
                                            Dan, See the file Inverter Module.jpg in FILES STEVE S FILES for the dimensions. All of the modules seem to have been somewhat hand built, so there is
                                            Message 21 of 22 , Jan 27, 2008
                                            • 0 Attachment
                                              Dan,

                                              See the file "Inverter Module.jpg" in FILES > STEVE'S FILES for the
                                              dimensions. All of the modules seem to have been somewhat hand built,
                                              so there is some variation from unit to unit. It's probably best to
                                              take the relative positions of the four pins from the mounting holes on
                                              the PMC8 board.

                                              Steve
                                              ============================
                                            • Dan Roganti
                                              I made a prototype of the DC/DC Converter using the switching regulator. Who was it that needed one to get their board running ? I can send you one to try out.
                                              Message 22 of 22 , Feb 10 8:26 PM
                                              • 0 Attachment

                                                I made a prototype of the DC/DC Converter using the switching regulator.
                                                Who was it that needed one to get their board running ?
                                                I can send you one to try out.
                                                I'll have a photo of this online soon

                                                =Dan

                                                Steve wrote:

                                                Dan,

                                                See the file "Inverter Module.jpg" in FILES > STEVE'S FILES for the
                                                dimensions. All of the modules seem to have been somewhat hand built,
                                                so there is some variation from unit to unit. It's probably best to
                                                take the relative positions of the four pins from the mounting holes on
                                                the PMC8 board.

                                                Steve


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