17 Aug
2021
17 Aug
'21
11:44 a.m.
I have a non-functioning H7868 PSU. This is one of the two PSUs used in
a BA214 chassis (and probably elsewhere).
This one seems to be dead: the green LED doesn't come on at all, there
is no sign of life and no +5V appears on the BA214 Qbus.
(I did use a load board when testing, so that's not the issue).
Does anyone have a set of schematics? I did try poking around in the
various MicroVAX 3600/3800 schematics that I could find on bitsavers but
nothing obvious leapt out at me. Of course, I could easily have missed
something.
Alternatively, does anyone have any experience of working on these PSUs?
Any pointers for common failure modes would be helpful.
Thanks
Antonio
--
Antonio Carlini
antonio at acarlini.com