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Re: [midatlanticretro] makeshift IBM monitor

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  • Bill Degnan
    Remember when you work with the manual not to confuse the directions and settings for the 16K-64K board and the 64K-640K board. They re both in the manual. I
    Message 1 of 23 , Jun 1, 2009
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      Remember when you work with the manual not to confuse the directions and
      settings for the 16K-64K board and the 64K-640K board. They're both in the
      manual. I have more info on my web site, vintagecomputer.net/ibm. Also
      search the blog for various notes and pictures about this model. I have
      restored three of these models in the past 12 months.

      Usually what kills them is the monitor card, usually if you replace the
      card the system comes back to life. The other likely thing to go wrong is
      RAM. I can teach you some tricks to locating the bad RAM and replacing.

      Bill

      -------- Original Message --------
      > From: "Joe Giliberti" <Starbase89@...>
      > Sent: Monday, June 01, 2009 3:03 PM
      > To: midatlanticretro@yahoogroups.com
      > Subject: Re: [midatlanticretro] makeshift IBM monitor
      >
      > I downloaded a PDF copy of the technical manual last night. I'm guessing
      the
      > onboard RAM are the 27 or so small chips near the front visible corner
      of
      > the board? I'll get all relevant information you asked for, including
      switch
      > positions, and get back to you.
      > Joe
      >
      > On Mon, Jun 1, 2009 at 2:55 PM, Bill Degnan <billdeg@...>
      wrote:
      >
      > >
      > >
      > > Joe,
      > > Do you have a copy of the technical reference manual? If not I can
      copy
      > > and scan the important pages. In the mean time can you take a picture
      of
      > > the motherboard switches, and RAM? If not easy to do, can you just tell
      me
      > > whether there are open RAM slots and what the switches are set to? I
      am
      > > guessing it's a 64K + 512K with the QuadRAM card = 640K. With this you
      > > could do almost anything. Lastly, what are the markings on the ROM
      chips
      > > in U33? That will tell me if it has an upgraded ROM or the original. I
      am
      > > going to guess that it's been upgraded.
      > >
      > > I don't off hand know the voltages. The 8087 coprocessor is next to
      the
      > > processor near the power connector.
      > >
      > > Thanks
      > > Bill
      > >
      > >
      > > -------- Original Message --------
      > > > From: "Joe Giliberti" <Starbase89@...
      <Starbase89%40gmail.com>>
      > > > Sent: Monday, June 01, 2009 2:45 PM
      > > > To:
      midatlanticretro@yahoogroups.com<midatlanticretro%40yahoogroups.com>
      > > > Subject: Re: [midatlanticretro] makeshift IBM monitor
      > > >
      > > > All I've done thus far is apply power to the power supply (which is
      > > > original). What are the voltages supposed to be going into the
      mainboard?
      > >
      > > I
      > > > want to check with a multimeter before hooking it to the
      motherboard.
      > > It
      > > > appears to have the co-processor installed. I do plan on doing a
      > > > methodological, slow restore on it.
      > > >
      > > > Aside from resocketing chips and removing dust, what is the
      procedure
      > > for
      > > > checking the motherboard?
      > > >
      > > > Joe
      > > >
      > > >
      > > > On Mon, Jun 1, 2009 at 9:38 AM, Bill Degnan
      <billdeg@...<billdeg%40degnanco.com>>
      > >
      > > wrote:
      > > >
      > > > >
      > > > >
      > > > > May I add that this is quite a lucky find, you may never get such
      a
      > > rare
      > > > > system in the trash ever again, you take this as an opportunity to
      > > perform
      > > > > a serious restoration/save. Learn about what you have and make the
      most
      > >
      > > of
      > > > > the experience. Don't try to hook this up to the Internet, try to
      > > return
      > > > > the computer to original condition. Don't power this up until
      you're
      > > > > confident you have tested the power, removed all cards and
      unhooked
      > > power
      > > > > to the motherboard, etc.
      > > > > Bill
      > > > >
      > > > >
      > > > > -------- Original Message --------
      > > > > > From: "Mr Ian Primus" <ian_primus@...
      <ian_primus%40yahoo.com>
      > > <ian_primus%40yahoo.com>>
      > > > > > Sent: Monday, June 01, 2009 8:08 AM
      > > > > > To:
      > > midatlanticretro@yahoogroups.com <midatlanticretro%40yahoogroups.com>
      > > <midatlanticretro%40yahoogroups.com>
      > > > > > Subject: Re: [midatlanticretro] makeshift IBM monitor
      > > > > >
      > > > > > --- On Sun, 5/31/09, Joe Giliberti
      > > <Starbase89@...
      <Starbase89%40gmail.com><Starbase89%40gmail.com>>
      > > > > wrote:
      > > > > >
      > > > > > >there is a bit of rust on the cover, but not significant. I'm
      using
      > > a
      > > > > >random AT keyboard, as I do not have a model M
      > > > > >
      > > > > > An AT keyboard will not work on this machine. You need an XT
      > > keyboard.
      > > > > The plugs are the same, but the protocol is different. Some early
      AT
      > > > > keyboards also have a switch (sometimes hidden behind a little
      panel in
      > >
      > > th
      > > > > bottom) to switch between AT and XT modes.
      > > > > >
      > > > > > The original CGA card has RCA plugs on it, and if I remember
      > > correctly,
      > > > > it should be composite video. But, I do believe that the composite
      > > video
      > > > > output does not support all video modes that the CGA card can do.
      Your
      > > best
      > > > >
      > > > > bet is to find a real monitor...
      > > > > >
      > > > > > You can't connect the CGA card to a VGA monitor, but you CAN use
      > > (with
      > > > > limited color palette), an analog RGB monitor, such as the ones
      used on
      > >
      > > the
      > > > >
      > > > > Commodore Amiga. CGA is a digital RGB, and uses an intensity line.
      The
      > > > > analog monitors will display the digital signal, but can't use the
      > > > > intensity line - so all the "light" colors come out as the same
      color
      > > as
      > > > > their "bright" counterparts. It's usable though.
      > > > > >
      > > > > > -Ian
      > > > > >
      > > > > >
      > > > > > ------------------------------------
      > > > > >
      > > > > > Yahoo! Groups Links
      > > > > >
      > > > > >
      > > > > >
      > > > >
      > > > >
      > > > >
      > >
      > >
      > >
    • Evan Koblentz
      ... Sorry to bog down the list in details. I meant to reply to Brian off-list.
      Message 2 of 23 , Jun 1, 2009
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        Evan, I'm available most evenings after 8pm. I think you have my cell phone #, if not, email my home e-mail and I'll send you that and my address..   
            
        Brian, can we meet at the mall (or some other central location) like we 
        did when you retrieved Chris' bag?
          
        Sorry to bog down the list in details.  I meant to reply to Brian off-list.
      • Joe Giliberti
        Here s as much info as I can pull off the mainboard Machine Serial: 0177038 On the planar: SW1 on on on on off on on off SW2 on off on on off off off off U28
        Message 3 of 23 , Jun 1, 2009
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          Here's as much info as I can pull off the mainboard

          Machine Serial:
          0177038

          On the planar:

          SW1
          on on on on off on on off

          SW2
          on off on on off off off off

          U28
          Empty Socket

          U29
          MK35748 J
          5700019
          ZA
          (copyright) IBM 1981
          D Malaysia
          8135 Q

          U30
          5700027
          (copyright) IBM 1981
          XE
          (motorola symbol) 8201BNM

          U31
          (motorola symbol) 5700035
          (copyright) IBM 1981
          XE8135ANM

          U32
          MK36728 P
          5700043
          ZA
          (copyright) IBM 1981
          D Malaysia
          8142 D

          U33
          MK36C35N-4
          1501476
          ZA
          (copyright) IBM CORP
          1981, 1983
          D Malaysia

          U34
          (not socketed)
          NEC
          PIY229-147
          D8253C-5

          Has a total of 36 of what I believe to be memory chips. Nine are soldered direct to the board, the remaining 27 are socketed
          The chips are marked:

          (AMD symbol) AM9016DPC
          8144WPP

          All 36 are the same chips


        • B Degnan
          U33 MK36C35N-4 1501476 ZA (copyright) IBM CORP 1981, 1983 D Malaysia Tells you it s a 2nd REV16K-64K (upgraded) ROM set. The first rev did not have a routine
          Message 4 of 23 , Jun 1, 2009
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            U33
            MK36C35N-4
            1501476
            ZA
            (copyright) IBM CORP
            1981, 1983
            D Malaysia

            Tells you it's a 2nd REV16K-64K (upgraded) ROM set.  The first rev did not have a routine for using hard drives, and some other things so most people upgraded the ROMS so they could use newer parts and memory.



            Here's as much info as I can pull off the mainboard

            Machine Serial:
            0177038
            this year I worked on the following other 16-64K boards, so yours is right in there among them, definitely an original, probably from late 1981 early 1983.:

            0159618
            0239462
            0192592 (MARCH's with original ROMS)

            On the planar:

            SW1
            on on on on off on on off

            SW2
            on off on on off off off off


            you have a full complement of RAM (64K) on the motherboard. 

            I assume you have SW1 reversed.  Up means "on" if facing from the front looking down. 
            If you have a co-processor, two drives, CGA monitor then SW1 should be: [off on -- -- on off off on] (where pertains to RAM).

            If SW1's 5 is up and 6 down  - that means CGA display.  Monochrome 5 and 6 are down.  Never mix and match without first changing the switches before powering on.  Otherwise you will fry the board and short the system.

            Math co-processor 2 = up/on.

            In a nutshell it looks like you have a standard configuration, no changes needed assuming you use a CGA monitor.  Don't try to use monochrome with these settings.  Someone did that to MARCH's 5150, and we had to replace the display card as a result. 

            Hope this helps.

            Bill

          • Joe Giliberti
            Thanks for the info, Bill Some more questions Does it matter whether I take video from the CGA port or the composite? So I could, if I wished, install an MFM
            Message 5 of 23 , Jun 1, 2009
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              Thanks for the info, Bill
              Some more questions

              Does it matter whether I take video from the CGA port or the composite?
              So I could, if I wished, install an MFM hard drive/controller, or perhaps a hardcard. Correct?
              Also, due to the different ROM, will it support a full 640k, or the 544k from the first gen?

              Joe

              On Mon, Jun 1, 2009 at 10:45 PM, B Degnan <billdeg@...> wrote:


              U33
              MK36C35N-4
              1501476
              ZA
              (copyright) IBM CORP
              1981, 1983
              D Malaysia

              Tells you it's a 2nd REV16K-64K (upgraded) ROM set.  The first rev did not have a routine for using hard drives, and some other things so most people upgraded the ROMS so they could use newer parts and memory.




              Here's as much info as I can pull off the mainboard

              Machine Serial:
              0177038
              this year I worked on the following other 16-64K boards, so yours is right in there among them, definitely an original, probably from late 1981 early 1983.:

              0159618
              0239462
              0192592 (MARCH's with original ROMS)


              On the planar:

              SW1
              on on on on off on on off

              SW2
              on off on on off off off off


              you have a full complement of RAM (64K) on the motherboard. 

              I assume you have SW1 reversed.  Up means "on" if facing from the front looking down. 
              If you have a co-processor, two drives, CGA monitor then SW1 should be: [off on -- -- on off off on] (where pertains to RAM).

              If SW1's 5 is up and 6 down  - that means CGA display.  Monochrome 5 and 6 are down.  Never mix and match without first changing the switches before powering on.  Otherwise you will fry the board and short the system.

              Math co-processor 2 = up/on.

              In a nutshell it looks like you have a standard configuration, no changes needed assuming you use a CGA monitor.  Don't try to use monochrome with these settings.  Someone did that to MARCH's 5150, and we had to replace the display card as a result. 

              Hope this helps.

              Bill


            • B Degnan
              ... only use a real cga monitor in the CGA port. do not use the composite. ... yes but this system did not come with a hard drive and would not be in the
              Message 6 of 23 , Jun 2, 2009
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                Joe Giliberti wrote:
                Thanks for the info, Bill
                Some more questions

                Does it matter whether I take video from the CGA port or the composite?
                only use a real cga monitor in the CGA port.  do not use the composite.

                So I could, if I wished, install an MFM hard drive/controller, or perhaps a hardcard. Correct?
                yes but this system did not come with a hard drive and would not be in the spirit of what it was originally.

                Also, due to the different ROM, will it support a full 640k, or the 544k from the first gen?

                full 640.  Should be at 640K now.
                Joe


                P.S. - Evan - the disk you gave me for the IBM at MARCH has some bare spots, the drive needs to be cleaned or replaced.    Do we have any replacement Tandon 100-2a drives at MARCH?

                Bill
              • Evan Koblentz
                ... I don t know.
                Message 7 of 23 , Jun 2, 2009
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                  > Evan - the disk you gave me for the IBM at MARCH has some bare spots,
                  > the drive needs to be cleaned or replaced. Do we have any
                  > replacement Tandon 100-2a drives at MARCH?
                  I don't know.
                • Mr Ian Primus
                  ... The drive probably just needs a good cleaning. I ve never seen a Tandon in an IBM fail so badly as to scrape up disks. The heads are probably just really
                  Message 8 of 23 , Jun 2, 2009
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                    --- On Tue, 6/2/09, Evan Koblentz <evan@...> wrote:

                    > > Evan - the disk you gave me for
                    > the IBM at MARCH has some bare spots,
                    > > the drive needs to be cleaned or replaced. 
                    >   Do we have any
                    > > replacement Tandon 100-2a drives at MARCH?
                    > I don't know.

                    The drive probably just needs a good cleaning. I've never seen a Tandon in an IBM fail so badly as to scrape up disks. The heads are probably just really dirty. Also, the disk itself could have been compromised - some brands are more apt to start shedding oxide with age.

                    -Ian
                  • Bill Degnan
                    ... in an IBM fail so badly as to scrape up disks. The heads are probably just really dirty. Also, the disk itself could have been compromised - some brands
                    Message 9 of 23 , Jun 2, 2009
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                      -------- Original Message --------
                      > From: "Mr Ian Primus" <ian_primus@...>
                      > Sent: Tuesday, June 02, 2009 8:56 PM
                      > To: midatlanticretro@yahoogroups.com
                      > Subject: Re: [midatlanticretro] Re: makeshift IBM monitor
                      >
                      > --- On Tue, 6/2/09, Evan Koblentz <evan@...> wrote:
                      >
                      > > > Evan - the disk you gave me for
                      > > the IBM at MARCH has some bare spots,
                      > > > the drive needs to be cleaned or replaced.
                      > > Do we have any
                      > > > replacement Tandon 100-2a drives at MARCH?
                      > > I don't know.
                      >
                      > The drive probably just needs a good cleaning. I've never seen a Tandon
                      in an IBM fail so badly as to scrape up disks. The heads are probably just
                      really dirty. Also, the disk itself could have been compromised - some
                      brands are more apt to start shedding oxide with age.
                      >

                      True on all counts. I was just curious about whether we had another drive
                      if next time I come up and I can't fix the problem, I can bring a spare
                      drive if I have one. Hopefully you're right and a good cleaning will
                      suffice, or a new disk. The disk in question is a copy of DOS 2.11 with a
                      few scratched tracks, but not completely bare. I never had issues with
                      these drives when I was working with the system myself, but I was mostly
                      focused on the hardware and did not do much disk exercising other than
                      format a disk in both drives.

                      bd
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