I successfully repaired my A3000 PSU a few years ago. There were 2 power transistors, a resistor and a small fuse which failed. You need a multi-meter, soldering equipment and a good eye to do this repair.
It's a good idea to check the cooling fan and inspect the electrolytic caps while your at it. With a switching PSU sometimes it's a simple repair and other times it's catastrophic (then your better off to hack in a replacement PSU).
Good luck!
