On 12/13/2015 09:22 AM, tony duell wrote:
I've done the obvious, reseating socketed ICs, checking the +12V and +5
rails, and checking the on-board CPU reset line. Does anyone have any tips
for what's best to try next?
Didn't at least some versions use 2114 RAM chips? If so, then check/change
those first
Yes, I've certainly seen that on the schematics, and was considering them
as a likely failure too - after opening cases though, my drives all seem to
have a single larger SRAM (even the Rev A board, so that's presumably "Rev
A of the type that doesn't use 2114's" :-)
While 2114's could be somewhat unreliable, I think the larger (6116 etc.)
SRAMs are generally OK; while a fault there is a possibility, I'm thinking
that the failure is likely elsewhere.
(Aside: Why on Earth do people scan schematics as bi-level images? I've not
found a good 1541 schematic yet - the ones out there are all high
resolution, but the depth reduction renders component information unreadable)
Jules
