My Sony PSP won't turn on even with power supply

@lacasique old question and somehow it popped up ;) First thing I'd do is to replace the battery. It is definitely no longer holding a charge. Always look for the easy stuff first :) and than make sure that the battery makes good contact.The PSP has fuses on the MB. It has 2 fuses (LD) One marked TB. The other is located beside the power cable disconnect. check those for continuity. If they do not have continuity that means that they have failed (actually they have done their job and protected the board). Please do not just bridge fuses. There is a reason why your device has those. If anything should shorten your board out again, the damage will be somewhere within other circuitry and component repair will be needed. It just makes your job harder.