After assembling an audio amp (LM386) for bench tests purposes and when looking for a speaker and enclosure I was surprised of how many failed amps for desktop PCs I had around!! After opening them: I noticed that in ALL, once plugged, the /edit AC from secondary /edit go straight to the rectifier. No switch in between. The ON switch at the front just applies that rectified voltage to the filter, feeding the amp. Found from discrete amps to TDA and TBA ICs. Found one PCB cracked by the pressure exerted on the ON switch and also a transformer heating madly even after desoldering all the components around. To complete my performance I opened the pair of this PC and replaced the failed pot with fixed resistors. Intput level software control does the rest. Two years ago I had replaced the filter cap when my daughter discarded it because of a severe buzz. To disassemble the pot I had to forcibly cut it because the nut inside a deep circular recess did not allow to free the shaft. I wonder how it was assembled but evidently nobody expected this to be repaired. They were all made in China. Oh God, music is so nice...!