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Re: [Altair Computer Club] 16k Static board for 680 system and more

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  • Dave Freeman
    ACP Components 1317 E. Edinger Santa Ana, CA 92705 ACP has several hundred 4200 chips in stock Call Jim for help. Thanks ... [Non-text portions of this message
    Message 1 of 16 , Jul 21, 2005
      ACP Components
      1317 E. Edinger
      Santa Ana, CA 92705
      ACP has several hundred 4200 chips in stock
      Call Jim for help.
      Thanks
      On Jul 20, 2005, at 3:58 PM, Craig Landrum wrote:

      > Bought what I thought was a bunch of 88-16MCS cards off
      > ebay some time back and looking at them now (while building up
      > my 8800), I found that one of them is a 680b-BSM static card
      > for a 680 system.  The board is really clean and I'd like to
      > either sell it or trade for an 8800 88-16MCS board. 
      >
      > I also have an 88-PMC8 8k EPROM board (uses 2708's) and board
      > description claims it can program proms - it's only
      > partially populated (all sockets and regulators are installed, but
      > board needs all of the 74xx bus interface/logic chips). Of course
      > this means that I'm now in the market for a 1702-based 88-PMC
      > prom card (which is what I thought I was getting).  If anyone
      > has one to sell or trade, let me know.
      >
      > FYI, I now have a small stock of 4200ACC static RAM chips for
      > the 16K boards if anyone needs one or two.
      >
      > Finally, I'm loooking for a pinout description of the cable that
      > runs from the two disk controller cards to the Altair 8 inch
      > disk unit.  one of the connectors on one end has been removed and
      > I'll have to replace it to get it working again. but I need
      > the pinouts.  Any help apppreciated.
      >
      >
      >
      > --
      > Craig Landrum
      > Chief Technical Officer
      > mindwrap, inc.
      > Phone: (540) 675-3015 x 229
      > Fax:   (540) 675-3130
      > email: craigl@...
      >
      >
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      [Non-text portions of this message have been removed]
    • Steve
      The 680 static RAM card uses the same chips as the 16K static RAM card for the 8800 buss. The PMC-8 board was often sold as a read-only board, without
      Message 2 of 16 , Jul 21, 2005
        The 680 static RAM card uses the same chips as the 16K static RAM
        card for the 8800 buss.

        The PMC-8 board was often sold as a read-only board, without
        programming ability. Does your board have a big rectangular inverter
        module mounted on it? If not, you can't blast 2708s.

        Which cable are you rebuilding? One of the internal cables that go
        from the 2 boards to the back panel of the computer, or the long
        cable that goes from the back of the Altair to the back of the drive
        cabinet? Or somewthing else?

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

        --- In altaircomputerclub@yahoogroups.com, Craig Landrum
        <craigl@m...> wrote:
        > Bought what I thought was a bunch of 88-16MCS cards off
        > ebay some time back and looking at them now (while building up
        > my 8800), I found that one of them is a 680b-BSM static card
        > for a 680 system. The board is really clean and I'd like to
        > either sell it or trade for an 8800 88-16MCS board.
        >
        > I also have an 88-PMC8 8k EPROM board (uses 2708's) and board
        > description claims it can program proms - it's only
        > partially populated (all sockets and regulators are installed, but
        > board needs all of the 74xx bus interface/logic chips). Of course
        > this means that I'm now in the market for a 1702-based 88-PMC
        > prom card (which is what I thought I was getting). If anyone
        > has one to sell or trade, let me know.
        >
        > FYI, I now have a small stock of 4200ACC static RAM chips for
        > the 16K boards if anyone needs one or two.
        >
        > Finally, I'm loooking for a pinout description of the cable that
        > runs from the two disk controller cards to the Altair 8 inch
        > disk unit. one of the connectors on one end has been removed and
        > I'll have to replace it to get it working again. but I need
        > the pinouts. Any help apppreciated.
        >
        >
        >
        > --
        > Craig Landrum
        > Chief Technical Officer
        > mindwrap, inc.
        > Phone: (540) 675-3015 x 229
        > Fax: (540) 675-3130
        > email: craigl@m...
      • Craig Landrum
        I m hoping someone in the group has experienced this before and can recommend a fix. (Oh, I know what THAT is...) The symptom: I have a MITS CPU card and two
        Message 3 of 16 , Jul 22, 2005
          I'm hoping someone in the group has experienced this before
          and can recommend a fix. (Oh, I know what THAT is...)

          The symptom:

          I have a MITS CPU card and two 16-MCS static cards installed.

          I turn all of the address line off and hit EXAMINE. Works.

          Then I turn on A0 and hit EXAMINE - doesn't work (the A0 light
          does not come on)

          Turn off A0, turn on A1, do EXAMINE - works

          Turn off A1, turn on A2, etc, etc through all the
          switches up to A14. Some work, some don't and I
          cannot find a pattern

          A14 - OK
          A13 - OK
          A12 - OK
          A11 - Bad
          A10 - Bad
          A9 - OK
          A8 - Bad
          A7 - OK
          A6 - Bad
          A5 - OK
          A4 - OK
          A3 - Bad
          A2 - Bad
          A1 - OK
          A0 - Bad

          My analysis:

          EXAMINE fires off a counter (IC J) that eventually results in
          three words being written to the D0-D7 lines that plug into
          the CPU board. These lines are pulled up with 4.7K resistors
          on the CPU board.

          The first count places an octal 303 (JMP) instruction on the
          bus. The second count places A0-A7 onto the D0-D7 lines, and
          the third count places the A8-A15 onto D0-D7. The fourth count
          lowers PRDY, placing the CPU in a wait state. All this is
          in the Theory of operation description for the front panel.

          All of the values are driven by 7405 chips, based on input
          from a 7404 (for the 303) and 7400 (for the address bytes).

          I hooked up a logic analyzer and verified that the 7404 and
          the 7400 were firing at the correct times - look nice and
          clean. I then went to the D0-D7 lines on the CPU board
          (easy to hook onto), to verify the output off the 7405's.
          Turns out that looking at these signals was very difficult
          (probably because the signals were flaky to begin with,
          hence causing my problem with the address lines, duh).
          Looking at the signal, the 7405 seem to work fine when
          they are required to output mostly 1's (set A0-A7 ON
          and hit EXAMINE), and seem to work when all but one are
          set to ON (A0 off, A1-A7 on for example). But when the
          switches are mostly off and one switch is ON (A0 On, A1-A7
          off), the rising edge of the "1" signal from the 7405
          appears ragged and takes a while to settle down, causing
          the CPU to think the line is "0" when it should be "1".

          I note that the A0-A7 and A8-A15 lines driven by the 7405's
          are as a result of input from one gate of a 7400 (one
          drives the top 8 bits and another 7400 drives the bottom
          8 bits). The 7404 drives four gates of another 7405, and
          this combination never seems to fail (the CPU always sees
          the JMP instruction, but fails on the addresses).

          Has anyone else experienced flaky EXAMINEs like I'm seeing
          here? I suspect that the 7405's have somehow gone "wimpy"
          and are not reponding as quickly to the 7400 input as they
          did in their younger years but this seems sort of silly
          that a chip would degrade rather than outright fail.

          Of course it could also be that the 7400 chips are flaky
          and my analyzer simply isn't catching it, somehow causing
          the 7405's to oscillate on a rising edge.

          Recommendations? Replace the 7400's?? Replace the 7405s??
          (I have 74LS00's and some SN7405N's handy). Or perhaps
          something is wrong that I am not seeing.

          Any help appreciated. Unless I can get EXAMINE working
          reliably, it's going to make booting sort of hit or miss :-)

          Also FYI:

          EXAMINE NEXT works fine (uses a different mechanism)
          DEPOSIT and DEPOSIT NEXT seem to work OK (DEPOSIT
          sometimes needs more than one hit to make it in).

          I can enter and run the following test program just fine:

          IN 333
          STA 200
          JMP 000

          When I examine location 200 it contains whatever the
          sense switches were set to. So memory and thee CPU
          seem to be able to work together OK.
          --
          Craig Landrum
          Chief Technical Officer
          mindwrap, inc.
          Phone: (540) 675-3015 x 229
          Fax: (540) 675-3130
          email: craigl@...
        • Craig Landrum
          ... Now it s Tom s 680 Static RAM card, since we traded :-) ... It looked like the PMC8 picture on the virtualaltair website, bit I don t think it had the
          Message 4 of 16 , Jul 22, 2005
            On Friday, July 22, 2005 at 1:11 AM, Steve sent:

            >The 680 static RAM card uses the same chips as the 16K static RAM
            >card for the 8800 buss.

            Now it's Tom's 680 Static RAM card, since we traded :-)

            >
            >The PMC-8 board was often sold as a read-only board, without
            >programming ability. Does your board have a big rectangular inverter
            >module mounted on it? If not, you can't blast 2708s.

            It looked like the PMC8 picture on the virtualaltair website,
            bit I don't think it had the switch and the inverter.
            >
            >Which cable are you rebuilding? One of the internal cables that go
            >from the 2 boards to the back panel of the computer, or the long
            >cable that goes from the back of the Altair to the back of the drive
            >cabinet? Or somewthing else?

            Boards to backplane. I have a twisted pair cable and one of
            the smaller molex connectors was cut off. Tom sent me the
            pinouts, but now I'm looking for the model # for a replacement
            molex (and those slide-in crimping contacts). This molex
            appears about half the size of the CPU molex....

            Any idea where to get a molex replacement???
            --
            Craig Landrum
            Chief Technical Officer
            mindwrap, inc.
            Phone: (540) 675-3015 x 229
            Fax: (540) 675-3130
            email: craigl@...
          • Craig Landrum
            After days of chip-level debugging sessions along with an Altair BASIC boot disk generously provided by Bob, I was able to boot and run BASIC last night. Had
            Message 5 of 16 , Aug 12, 2005
              After days of chip-level debugging sessions along with an
              Altair BASIC boot disk generously provided by Bob, I was
              able to boot and run BASIC last night.

              Had previously been debugging the 88-DCDD system which
              had been assembled piecemeal from various sources
              (controllers from vintagemicros, disk drive from Jack,
              connector cable from Jameco, and plenty of great advice
              from Tom and others, a DCDD manual and DBL boot prom from
              Steve) and had fixed a defective braided cable, replaced
              a bad molex connector, and replaced four dead IC's on the
              controller cards.

              Last night (before I booted BASIC) I was running down a write
              problem using I/O test routines laboriously toggled in
              through the front panel. I would try a write and then
              try a read and get back all 1's. After hours of tracing
              signals using the logic analyzer and checking one-shot
              timings, I finally looked where I should have started
              at in the first place which was the actual connector on
              the back of the disk, and lo and behold, write data was
              streaming into the disk. WTF??? Data screaming in and
              nothing getting written? About 60 seconds later I
              slapped myself on the forehead, removed the diskette,
              and covered over the write protect tab. Duh. Stuff
              worked perfectly then, amazingly enough. Put the
              boot disk in and away we went. Lesson learned.

              Now that the system is alive, I'll try and do a
              facial makeover. The front dress panel is in
              really decent shape except for a few missing letters
              here and there. I grabbed a high rez scan of a
              good front panel from the web, Cleaned it up, removed
              the gray background, inverted the white bits to black
              and printed it actual size on clear mylar. I plan to
              use PhotoEZ to create a new silkscreen for portions of
              the front panel that are damaged (this is a neat
              product - see: http://www.gwengibson.com/photoez.htm
              I used it before when restoring the lettering on a
              rebuilt Chatauqua roller organ ). Will take some before
              and after pics of the dress panel.

              Stuff I'm still looking for:

              - A 88-CENT Centronics board (will buy if found or
              trade for other S100 boards)

              - A copy of Altair DOS/Editor/Assembler/Linker/Debugger

              - A second Altair Disk drive in its cabinet.

              - A repro Altair Disk aliminum dress strip to go on
              the front of the Altair Disk I now have. FYI, the
              guy that currently sells the Altair 8800 repro
              strips doesn't have them).

              I'm driving up to NJ in a week or so to pick up three
              ASR33 teletype/paper tape punch/readers and will
              rebuild one to go with this system.



              --
              Craig Landrum
              Chief Technical Officer
              mindwrap, inc.
              Phone: (540) 675-3015 x 229
              Fax: (540) 675-3130
              email: craigl@...
            • Steve
              Congratulations, Craig. It s always the simple things that cause the biggest headaches, isn t it? I m curious about your PhotoEZ project. After going to the
              Message 6 of 16 , Aug 12, 2005
                Congratulations, Craig. It's always the simple things that cause the
                biggest headaches, isn't it?

                I'm curious about your PhotoEZ project. After going to the URL you
                gave, and after googling for the product, it seems that the largest
                sheet of PhotoEZ is only 12" long. How will you able to produce a
                good ~17" silkscreen mask? Surely, you can't simply splice 2 sheets
                together, can you?

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

                --- In altaircomputerclub@yahoogroups.com, Craig Landrum
                <craigl@m...> wrote:
                > After days of chip-level debugging sessions along with an
                > Altair BASIC boot disk generously provided by Bob, I was
                > able to boot and run BASIC last night.
                >
                > Had previously been debugging the 88-DCDD system which
                > had been assembled piecemeal from various sources
                > (controllers from vintagemicros, disk drive from Jack,
                > connector cable from Jameco, and plenty of great advice
                > from Tom and others, a DCDD manual and DBL boot prom from
                > Steve) and had fixed a defective braided cable, replaced
                > a bad molex connector, and replaced four dead IC's on the
                > controller cards.
                >
                > Last night (before I booted BASIC) I was running down a write
                > problem using I/O test routines laboriously toggled in
                > through the front panel. I would try a write and then
                > try a read and get back all 1's. After hours of tracing
                > signals using the logic analyzer and checking one-shot
                > timings, I finally looked where I should have started
                > at in the first place which was the actual connector on
                > the back of the disk, and lo and behold, write data was
                > streaming into the disk. WTF??? Data screaming in and
                > nothing getting written? About 60 seconds later I
                > slapped myself on the forehead, removed the diskette,
                > and covered over the write protect tab. Duh. Stuff
                > worked perfectly then, amazingly enough. Put the
                > boot disk in and away we went. Lesson learned.
                >
                > Now that the system is alive, I'll try and do a
                > facial makeover. The front dress panel is in
                > really decent shape except for a few missing letters
                > here and there. I grabbed a high rez scan of a
                > good front panel from the web, Cleaned it up, removed
                > the gray background, inverted the white bits to black
                > and printed it actual size on clear mylar. I plan to
                > use PhotoEZ to create a new silkscreen for portions of
                > the front panel that are damaged (this is a neat
                > product - see: http://www.gwengibson.com/photoez.htm
                > I used it before when restoring the lettering on a
                > rebuilt Chatauqua roller organ ). Will take some before
                > and after pics of the dress panel.
                >
                > Stuff I'm still looking for:
                >
                > - A 88-CENT Centronics board (will buy if found or
                > trade for other S100 boards)
                >
                > - A copy of Altair DOS/Editor/Assembler/Linker/Debugger
                >
                > - A second Altair Disk drive in its cabinet.
                >
                > - A repro Altair Disk aliminum dress strip to go on
                > the front of the Altair Disk I now have. FYI, the
                > guy that currently sells the Altair 8800 repro
                > strips doesn't have them).
                >
                > I'm driving up to NJ in a week or so to pick up three
                > ASR33 teletype/paper tape punch/readers and will
                > rebuild one to go with this system.
                >
                >
                >
                > --
                > Craig Landrum
                > Chief Technical Officer
                > mindwrap, inc.
                > Phone: (540) 675-3015 x 229
                > Fax: (540) 675-3130
                > email: craigl@m...
              • Craig Landrum
                ... Correct - their sheets aren t large enough. Also, due to the small variations and inaccuracies in scanning, printing, etc, it is highly unlikely that I
                Message 7 of 16 , Aug 12, 2005
                  >I'm curious about your PhotoEZ project. After going to the URL you
                  >gave, and after googling for the product, it seems that the largest
                  >sheet of PhotoEZ is only 12" long. How will you able to produce a
                  >good ~17" silkscreen mask? Surely, you can't simply splice 2 sheets
                  >together, can you?
                  >
                  >steve

                  Correct - their sheets aren't large enough. Also, due to the
                  small variations and inaccuracies in scanning, printing, etc,
                  it is highly unlikely that I could generate a mylar or a
                  screen that would accurately register across the entire front
                  panel (at least not without a lot of tweaking). So what I'm
                  doing is simply making small screens that do specific
                  sections of the panel (perhaps for just one switch like the
                  ON/ OFF or EXAMINE/EXAMINE NEXT switch etc). Then I easily
                  mount the screen over the area being fixed with nice registration
                  and mask off the rest of the front panel with platsic wrap or
                  several sheets of paper, etc leaving just the area being painted
                  open.

                  PhotoEZ worked well for me when restenciling black letters over
                  polyurethaned wood and I would expect it to work even better
                  over smooth metal. On the wood project I was using Krylon
                  black spay paint and will probably try and use white or cream
                  color for the front panel. Haven't looked with a magnifier
                  yet, but at first glance the original white lettering appears
                  to be in semi-gloss or flat, so I will try that.

                  When doing these kind of things, the biggest ooops to avoid
                  is trying to apply too much paint at once, causing it to
                  wick between the stencil and the surface being painted.

                  I'm also considering spraying a final covering of clear satin
                  finish over the restored panel to protect it, but will certainly
                  try a small section first to see how it affects the appearance.
                  I wouldn't want to end up with nicely restored but fakey looking
                  panel....

                  --
                  Craig Landrum
                  Chief Technical Officer
                  mindwrap, inc.
                  Phone: (540) 675-3015 x 229
                  Fax: (540) 675-3130
                  email: craigl@...
                • Craig Landrum
                  I m considering creating some reproduction MITS documentation binders in something like 1 inch and 1.5 or 2 inch sizes. My initial thoughts were to duplicate
                  Message 8 of 16 , Aug 12, 2005
                    I'm considering creating some reproduction MITS documentation
                    binders in something like 1 inch and 1.5 or 2 inch sizes.

                    My initial thoughts were to duplicate the MITS blue lettering
                    etc on the cover and binding and also order the binders with
                    inside pockets and the clear plastic binder pocket that you
                    can slip a document title into.

                    Has anyone done this already? If not, would anyone be
                    interested in buying some from me if I ordered them in
                    quantity? Assuming I could charge about $5 a binder, would
                    there be any takers out there, and for how many binders?

                    --
                    Craig Landrum
                    Chief Technical Officer
                    mindwrap, inc.
                    Phone: (540) 675-3015 x 229
                    Fax: (540) 675-3130
                    email: craigl@...
                  • raife_e
                    ... wrote: ... Hi, I am currently looking for an aluminum 8800 repro strip , if I can t get an original. But, I don t know where to acquire one. Could you
                    Message 9 of 16 , Aug 14, 2005
                      --- In altaircomputerclub@yahoogroups.com, Craig Landrum <craigl@m...>
                      wrote:

                      ...

                      > - A repro Altair Disk aliminum dress strip to go on
                      > the front of the Altair Disk I now have. FYI, the
                      > guy that currently sells the Altair 8800 repro
                      > strips doesn't have them).

                      Hi,

                      I am currently looking for an aluminum "8800 repro
                      strip", if I can't get an original. But, I don't know
                      where to acquire one.
                      Could you point me to "...the guy that currently
                      sells the Altair 8800 repro strips"..?

                      Much appreciated,

                      Raife Edwards
                    • Craig Landrum
                      ... This was the email of the guy I bought mine from a month or so ago. At that time, he charged about $40 and $10 for shipping and the item was excellent.
                      Message 10 of 16 , Aug 15, 2005
                        On Monday, August 15, 2005 at 8:08 PM, raife_e sent:

                        > I am currently looking for an aluminum "8800 repro
                        >strip", if I can't get an original. But, I don't know
                        >where to acquire one.
                        > Could you point me to "...the guy that currently
                        >sells the Altair 8800 repro strips"..?
                        >
                        >Much appreciated,
                        >
                        >Raife Edwards
                        >

                        This was the email of the guy I bought mine from a month
                        or so ago. At that time, he charged about $40 and $10
                        for shipping and the item was excellent.

                        jerry.schneider@...


                        --
                        Craig Landrum
                        Chief Technical Officer
                        mindwrap, inc.
                        Phone: (540) 675-3015 x 229
                        Fax: (540) 675-3130
                        email: craigl@...
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