> -----Original Message----- > From: cctalk [mailto:[email protected]] On Behalf Of Mattis Lind > Sent: 02 November 2015 21:44 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: Testing H7864 (MicroVAX II) PSU With No Load > > 2015-11-02 22:05 GMT+01:00 Robert Jarratt <[email protected]>: > > > > > > > > > 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) > > /Mattis
Thanks for spotting the drawing mistake. I have noted an apparent short before, and I have some notes I made at the time, but that was so long ago (almost a year!), and the notes don't seem to conclude whether I found the short or not. I think I may have put it down to some of the transformers at the time, but I can't be sure. I will investigate this further as this is quite promising, but it looks like I will need to desolder some components... Regards Rob
