View Full Version : unknown isa card - Z80 SBC?

November 5th, 2017, 01:13 AM
Sorting through a massive haul of parts taking inventory, I came across this card:

http://i.imgur.com/koDbwDVm.jpg (https://imgur.com/koDbwDV) http://i.imgur.com/60nYnmZm.jpg?1 (https://imgur.com/60nYnmZ)

I like to think I can ID a part, but this one has gotten the better of me.

The west german srams are a nice touch! The picture will blow up so all the parts are easy to read. My best guess is a Single Board Computer of some flavor. I did also find a Kaypro version in all these boxes. :P The connector on the rear is a 25-pin male (like the original serial ports)

November 5th, 2017, 03:55 AM
Interesting it has one MC1488 RS-232 quad line driver and one SN75174 which is a quad differential line driver usually used for 422 or RS-485, the you have three SN75173s which is a quad differential line receiver which are also good for 422 or RS-485. Them there is one where the printinting is worn/rubbed off.

If it fits a PC could be some kind of controller board - first step I would take is to dump the eprom and disassemble it.


November 5th, 2017, 07:39 AM
Seconded. That will probably tell you who made it and what its application was. There were quite a few co-processor cards made for ISA in the early days, so it's not unusual in the sense of rarity.

November 5th, 2017, 08:53 AM
There is practically nothing on that am2764a chip, just 217 lines of code. Nothing to immediately identify anything. I've included a dump and subsequent disassembly below. Note, I've truncated the file after the last jump. I'm not familiar with z80 assembly, but if it's anything like 8051 this doesn't look like it is doing very much. Again, I could be completely wrong, it's all Greek to me.