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

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  • 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 1 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 2 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 3 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 4 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 5 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 6 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
                > > >
                > > >
                > > >
                > > >
                > > >



                Never miss a thing. Make Yahoo your homepage.

                No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.17.13/1210 - Release Date: 1/5/2008 11:46 AM
              • 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 7 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
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  >


                  No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.17.13/1210 - Release Date: 1/5/2008 11:46 AM
                • 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 8 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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                    Checked by AVG Free Edition.
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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 9 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.

                      No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.17.13/1210 - Release Date: 1/5/2008 11:46 AM



                      Looking for last minute shopping deals? Find them fast with Yahoo! Search.

                      No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.17.13/1210 - Release Date: 1/5/2008 11:46 AM
                    • 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 10 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 11 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 12 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


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                          • 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 13 of 22 , Jan 27, 2008
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                              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 14 of 22 , Jan 27, 2008
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                                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 15 of 22 , Feb 10, 2008
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                                  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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