Commodore PC-20-III

From: Cameron Kaiser <>
Date: Fri Apr 26 20:12:17 2002

> A little more information, now that I've found my folder of PC10/PC20
> schematics...
> The 'motherboard' is really I/O only (looks to be a serial port, a
> parallel port, and an FDC). The CPU card plugs into a special slot on
> this board -- it appears the CPU is an 8088 with (optional?) 8087
> coprocessor.
> There were at least 3 video cards : Monochrome (looks to be MDA), Color
> (looks to be CGA) and 'Advanced Monochrome' (looks to be Hercules). I
> can't be absolutely sure about that because all the cards have programmed
> PALs or PLAs on them and I don't have any info on what's inside them. The
> only one to have a composite output is the Color one. And none of them
> have DIP switches that I can see.
> So I would guess the card you have with the DIP switches is a generic
> clone card. As is the one with the 2 DA15s on it.

For some ungodly reason I can't find a screwdriver around here to open the
case, but I did boot the machine up. It seems to have DOS 3.21 on it but
the Commodore-specific tools I distantly remember having to use are still
there such as the software SPEED.EXE and something called SETCLOCK.

The card is, unbelievably, VGA -- it's a Cirrus Logic of some iteration
based on the startup with an Award BIOS?

The disk seems to be around 20MB. I'm assuming this is *not* IDE.
Whoever had this last made a hash out of it, files scattered everywhere :-P

The BIOS identifies itself as (C)1986 Commodore Electronics Ltd and seems
to be a Phoenix type. I can't figure out how to get into the BIOS setup.
Neat feature: all the devices are identified with their detected port

There is a SHIPDISK.COM utility which I'm assuming parks the heads, unless
people have another suggestion. Hope so, since this machine will travel about
120 miles on Sunday :-)

Any other ideas until I can get some tools to crack this open and clean up?

----------------------------- personal page: --
 Cameron Kaiser, Point Loma Nazarene University *
-- Mmmm, Windows user. Crunchy and good with ketchup. -- Dave McGuire ---------
Received on Fri Apr 26 2002 - 20:12:17 BST

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