The National MM5290's were, essentially, just another version of the 4116, a 16-K-bit 3-voltage dynamic RAM. I've got some doubts about the TMS4045's as well. I think you may be surprised to learn that they are essentially 2114's, (slow 2148's) which are 1kx4 as opposed to 4kx1. The 4kx1 SRAMS (slow 2147's) were 4044's. I doubt you'll have as much trouble fixing that board by unsoldering as you'd have today. Modern boards have large ground and power plane layers which sink heat much better than those old 2-layer boards allowed. There's a good chance that I've got one in the basement. If needed, I can probably identify the parts for you if nothing else. Dick ---------- From: Barry A. Watzman <Watzman(a)ibm.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Subject: Help - S-100 board info needed Date: Tuesday, February 16, 1999 4:57 PM I need information on two S-100 cards that I have acquired with no manuals. If someone has manuals on these, I'd pay a nominal fee for a copy, but in the meantime I'd like switch and jumper info. Card #1 is a Vector Graphic 64k RAM card. The card uses four rows of National Semiconductor MM5290 chips. There is one dip switch, 8 position, and lots of jumpers. Also, some circuitry that is not populated [U17, U18, U32 and a number of discreet components]. What are the 5290's, are these static or dynamic ? I was presuming it was DRAM, but I was expecting 4 rows of 4116's. Bad news, the memory chips and most of the support chips are soldered and are not socketed, which will be tough to fix if it doesn't work [and for a 20+ year old board, the chances that it works are not that good]. Can anyone help ? Card #2 is a Problem Solver Systems {PSS} Ram 16, a 16k static board with TMS4045 chips [those are 4k x 1 static rams, good chips, I have LOTS of experience with them and even some spare chips]. Two dip switches, one toggle switch and lots of jumpers. Need info. Anyone who can help, thanks in advance ! Regards, Barry Watzman Watzman(a)ibm.net ----------