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pjh
January 27th, 2016, 07:56 PM
I am looking for a Dual Systems CMEM memory board manual. If the manual is not available, I am hoping that someone else has a CMEM board and can tell me what ICs go in positions U30 and U40. As can be seen in the pictures these two chips are missing.

Thanks,
Phillip


2927329274

amouse
January 28th, 2016, 12:57 AM
Yes, unfortunately I can categorically state that DUAL documentation is just almost non existent. I googled it so many times of the years. So I would very much lookforward to somebody out there reading this and proving me wrong.

Regards marcus b.

pjh
February 13th, 2016, 08:30 PM
Just a followup on the CMEM board. I managed to find two pictures of the board online, neither of which are very clear. However, I was able to determine from one that the U40 chip is a 74LS245. That left the U30 chip to figure out. I traced back from all of the pins of U30 enough to determine how it functioned in the circuit. I realized that the chip must be a quad dual input nand chip which is a 74LS00. I installed both chips and had a successful test of the board. So, I now have a working CMEM static memory board.

Phillip