H7868 Power Supply Schematics

Antonio Carlini a.carlini at ntlworld.com
Tue Aug 17 13:44:35 CDT 2021

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 

Alternatively, does anyone have any experience of working on these PSUs? 
Any pointers for common failure modes would be helpful.



Antonio Carlini
antonio at acarlini.com

More information about the cctalk mailing list