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12859Re: [midatlanticretro] makeshift IBM monitor

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  • Bill Degnan
    Jun 1, 2009
    • 0 Attachment
      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@...>
      > Sent: Monday, June 01, 2009 2:45 PM
      > To: midatlanticretro@yahoogroups.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@...>
      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>>
      > > > Sent: Monday, June 01, 2009 8:08 AM
      > > > To:
      midatlanticretro@yahoogroups.com<midatlanticretro%40yahoogroups.com>
      > > > Subject: Re: [midatlanticretro] makeshift IBM monitor
      > > >
      > > > --- On Sun, 5/31/09, Joe Giliberti
      <Starbase89@...<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
      > > >
      > > >
      > > >
      > >
      > >
      > >
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