Testing H7864 (MicroVAX II) PSU With No Load

Mattis Lind mattislind at gmail.com
Mon Nov 2 15:44:25 CST 2015

2015-11-02 22:05 GMT+01:00 Robert Jarratt <robert.jarratt at ntlworld.com>:

> I have just uploaded all the corrections. So the connector names on the
> risers should now correspond. I have also corrected the area on the primary
> control module around C403 and R407.
> Regards
> Rob
Checked the new one. There are still something weird. The base of Q301 it
is short circuited to the emitter (which if that is true would of cause
your problem). But I think this is a drawing mistake. The base signals goes
to the D405 diode which is connected to emitter Q405 and emitter Q406 which
is then connected to emitter Q301...  Please check this again. Maybe there
are a short circuit component that makes you trace it wrong (if you do it
by ohm-meter)


More information about the cctech mailing list