Help w/DEC H742 +15V...

[Josh Dersch]

So I'm now the proud father of a DEC PDP 11/40, which should be a fun 
project/adventure to get running again.

I have been testing out the power supply and everything looked good this 
morning, at which point I figured I'd populate the CPU backplane and see 
what would happen.  The answer is: not much -- occasionally a few LEDs 
would light up, but the machine was completely unresponsive.

I went a bit further and tested the voltages at the backplane, and while 
checking the +15V, my probe slipped momentarily, bumping a nearby 
wirewrap pin, causing a small spark.  Now, where I once had +15V, I have 
0V.  And since the -15V regulator is powered (in part) from the +15V 
line, that's dead too.

I was hoping, after reading through the documents again, that it would 
be something as simple as fuse F1 on the power control board, but no 
such luck.  The fuse is still good.

Any suggestions for what's most likely to have blown when I screwed up 
here?  Any recommendations for working on this supply? I'm really 
looking forward to pulling this thing out of the rack to work on it -- 
this thing looks heavy :)

Thanks,
Josh (still slapping himself for screwing this up...)