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OSI 530 board on ebay

Posted: Wed Jul 05, 2017 3:44 am
by Steve Gray
Hi,

I see an OSI530 board on ebay. Haven't seen this before:

http://www.ebay.ca/itm/1977-Ohio-Scient ... 2019185381

Steve

Re: OSI 530 board on ebay

Posted: Thu Jul 06, 2017 2:45 am
by dave
Thanks for pointing it out--It looks like a nice specimen.

I think I may have one of these. I didn't give it much attention because it uses the relatively hard to get 4027 4k x 1 chip and uses multiple voltages. However, looking at the data sheet, it should be possible to substitute more common 4116 chips without any change to the voltage supplies, just strapping the CS pin high or low; or even use 4164 chips, which are even more common, require only +5, and are cheaper, but would require additional (but simple) modifications to the power rails.

Maybe it's worth revisiting the board, possibly even scanning one, to have a genuine period-correct RAM option that can fit 48K in a single board.

Dave