Yeah... so some more bits arrived to make the magic thing I've been making (deadline for completion being, Friday). So, I put it in the box... wired up the circuit boards and turned on the power.
"Stop!", shouts Paul, as smoke rises from between my legs.
I quickly turn off the power supply - as yer do. Then came the guessing game of what made the smoke... couldn't and blow chips or stuff (and there was a lot of smoke, so something should be obvious!). Then I realised it was the 0V wire going between two boards on my data ribbon... it was like no longer insulated, and was caked in crap.
Then I found the short circuit on the secondry board... so I'd put about 25Amps from the high powered supply (at 12V) down an ickle wire meant for about an Amp. Whoops.
When replacing the wire stuff still didn't work :( Bastards. I've since spent a large part of the evening trying to find out... it appears that I blew the PIC up... even though it appears to be doing the right things... very bloody odd. Least I seem to have got it all working again... grrrr.