Yep. That is the schematic I scanned. I posted it to cctalk last year, but forgot to cc Al Kossow. So it didn't end up bitsavers apparently. Got to fix that. It was an ex DEC field engineer that gave it to me. http://storage.datormuseum.se/u/9693...g-drawings.pdf

My experience is that it is very unlikely that transformer goes bad. With the exception of one FBT I had no transformer going bad at all. When the PSU ticks it is very likely that it tries to start up but discover some kind of situation that causes it to turn off immediately. Over current situation is in my experience most common source. That could be the load itself or faulty output rectifiers.

Check all the output rectifiers. Disconnect the load and use a proper dummy load. Some PSU don't like to have uneven load. Depending on how the regulation is done uneven load could cause crowbar circuit to trap and then there is over current situation as a result. In this case I cannot see any crowbar in the circuit. It seems to regulate on the sum of the 41V and 5V.

Could be an electrolytic cap that is bad, but have yet to see an electrolytic go short circuit, more often I have seen them go open circuit or low capacitance. Tantalum capacitors on the other hand is a completely different story.