So, here's the problem: I have a dead computer power supply that I want to fix to use for my electronics projects. Only problem here being that it's dead. I've looked at the board and identified the following component as the culprit (how, you may ask? the scorch marks around it, of course!):
A search that I went through said that this could either be a zener diode or a transistor (thinking it's probably a transistor...). The markings on the chip are: C5249, beneath that: 9N. I can't tell what the mark above it is, i'm assuming a manufacturer.
Since its a 600V transistor the chances are its running at mains voltage and was taken out by long term fatigue or by spikes on the supply - if you can find a replacement with superior specs that might be a useful precaution.
There may well be other fried parts of course as has been pointed out...
At the very least check the input for shorts before going further - also check the fan is working (it might have been an overheating failure due to a stuck fan).
bingo! And yes i've checked everything connected to that part up to two components away... and all the large major ones. I'm thinking this was due to an inadaquate heat sink, and generally getting too hot. Can't tell for sure right now but i'll buy a couple extras for the repair just in case. Thanks to BroHogan for the find