5 Dec
2015
5 Dec
'15
11:12 a.m.
There seems to be a spike on the 12V supply, surely that isn't good, even if
it doesn't affect the memory?
Often a spike on a particular output of an SMPSU is caused by a high ESR capacitor
on that output. It's worth checking them.
FWIW, old DRAMs, up to about 16Kbit size, often used +12V and -5V as well as +5V.
Later/larger DRAMs are +5V only. I doubt you'll find any of the former in a VAX after
early 11/700-series.
-tony