PC/AT memory boards

From: Gordon C. Zaft <zaft_at_azstarnet.com>
Date: Wed Aug 29 23:46:11 2001

        I've got an old genuine IBM AT (8 MHz) that has a couple of 16bit mystery
boards in it...

        1) Marked 55x3543, google says 0.5 to 3 MB board. It has a 16450 on it, a
total of 12 30 pin simms, a male DB9 (okay, I guess it's a DE9) and a
female DB25. I assumed it was a serial port and parallel port but it
doesn't show up as such in the machine. Also since these appear to be 256K
simms I expected the machine to boot with 2MB of RAM or more but it only
came up as 1 MB. I'm suspecting it's configured wrong or there's a
conflict but of course I don't have any docs... anyone?

        2) Another memory board, 18 256Kbit chips, marked EV159 and has a big
EVEREX chip on it. Google says 3 MB expansion board, same questions. I
assume this motherboard has 512K on it, so... this board might be okay but
I'd like to know what the switch settings are in case I decide to add
memory to it (anyone know a cheap source of 41256s?

        Any help (docs especially) would be appreciated....

Gordon Zaft
zaft_at_azstarnet.com
Received on Wed Aug 29 2001 - 23:46:11 BST