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HiI recently got a Apple IIe with a strange 80 column & memory expansion card. At least I assume it's such a card. The only Information I see on the PCB is "Copyright 1988 MKV". No further Information on the back.
Interestingly all the chips on the board where manufactured in 1983 (according to production code labled on them).Any idea who was the manufacturer or available documentation for the board? - would be greatly appreciated.
Peter
It looks like a generic clone 80 column card with 64k. There were dozens of them on the market back then. The Copyright date is a little later than what I'd expect for this kind of design. By 1988 most of the 80 column designs were featuring larger memory size or reduced chip count. I can't read the DRAM chip part numbers. It is possible that this card has a larget RAM amount.
Zooming in they are Mostek branded 4564 DRAM chips (64k x 1) which are equivalent to 4164s.
This is a one-for-one direct copy of the Apple 64K 80 column card, jumper included.
Judging from the capacitor substitutions on the first and last RAM chips this card was definitely designed (if you can call direct copying "design") and built on the cheap.
That's pretty much what I expected, but thanks for taking the effort to look. I just wasn't sure.
It's not to say it's bad - it will be perfectly functional as long as those Mostek chips hold out. And it's a cool piece of gear.
I have a thing for clone hardware and its many ingenious ways of copying original cards.
Thank you all for your research. At the first glance, the card seems to work. Probably going to replace all capacitors. Still a lot of work to be done restoring the IIe.
Don't bother. Those are ceramic capacitors and will not deteriorate.
There's a higher probability that you'll make the card worse instead of better.
They are ceramic capacitors except for the ones at the outer ends of the row. Those are tantalum capacitors and they're not intendt to be used as blocking caps for ICs.
I don't think this was the designers intention.