Replacing MicroVAX II PSU With a Modern PSU

Robert Jarratt robert.jarratt at
Thu Nov 19 18:00:58 CST 2015

While I look into what is wrong with my H7864, I'd like to use a modern PSU
to power my machine (actually an rtVAX 1000).


I think I would need to deal with the following problems:


1.       Finding the right connectors (ideally, I am sure I could rig up
something more temporary).

2.       A way to power the fans, which I believe are 15V, perhaps they
would run on 12V as I wouldn't run the machine for long periods anyway, or I
could just use PC fans.

3.       Emulate the DC OK and P OK signals, I suspect these would be simple
+5V signals which could perhaps just come from the +5V of the PSU anyway
(unless there is a problem with that).

4.       The most difficult bit, I suspect, would be the PSU LTC signal ,
which I believe is some kind of clock. I don't know what the spec of the
signal is, but I will get a scope on a working one to see (NB don't want to
risk a working PSU on this machine in case it was a problem with the machine
itself that caused the first PSU to fail, I don't mind sacrificing a modern
PSU if need be).


Has anyone done this before?





More information about the cctech mailing list