I have a commercial tester for 64 and 256K chips. It's reliable to the point of "good or bad" detects shorts in the circuit. If you live near Landenberg, PA feel free to stop by to use it. Bill On Thu, Sep 14, 2017 at 6:24 PM, John Heritage via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Hey folks,
I've come across an old PC XT motherboard that's sat in a dirty warehouse for a long time. It has 18 x 41256 and 18 x 4164 (640KB total + parity) RAM chips.
Knowing that i've needed some of these in the past to repair my old Atari computers, I'd like to test these individual RAM chips somehow, but preferably without abusing the old sockets on my Atari's..
Does anyone know of a relatively simple circuit I can build to test these chips directly?
The 4164s come on the Atari 600XL, 800XL, 1200XL and 130XE, and the 41256 come on the 4-chip versions of the 130XE. The micron 4164's that came on a lot of old Atari's are just flat out dying (I had 3 x 800XLs out of 7 that had bad ram), so these are handy for that or other communities.
Thanks! John