Weird S100 memory board problem - test-drb@ccmp.vtda.org

23 Jul 2005

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Subject: Weird S100 memory board problem
   From: "Richard A. Cini" <rcini at optonline.net>
   Date: Fri, 22 Jul 2005 22:57:54 -0400
     To: CCTalk <cctalk at classiccmp.org>

All:

	I have a CompuPro/Godbout RAM14 (16kx8) board, arranged in 4 banks
of 4k starting at 0. I ran a memory test program on it and it shows address
0x3000 as failing; when you look at data written, it appears that BIT 0 is
bad.

	So, I ordered some 2147 chips from JDR and swapped the bad chip. It
still fails the same bit. So, I swapped it with another chip in the row, and
it fails again. It passes at address 1000 and 2000, so it can't be an
address bit buffer chip.

	Any ideas? Where should I look next? 
Sounds like a data buffer problem either in the data in lines or 
data out lines.  Or it could be the data in or out line for that 
bit is bad to the chip (socket or open trace).

Allison


Allison