Switch Mode PSUs are basically a combination of magic and voodoo. Theoretically they're easy/cheap to fix but I don't pretend to understand them and the high voltages on the board usually deter me from trying.
This explains the design and common modes of failure:-
http://www.repairfaq.org/sam/smpsfaq.htmGood luck! Remember to sacrifice the appropriate animals at the correct points in the moon's cycle.
Steve
