Disconnect the speakers from the terminals on the amp. Turn it on and see how long it stays on. If it still goes off, its the amp. I think it will stay on though. If it does turn the stereo off, connect one speaker and turn the stereo back on. See if it stays on. Repeat this with all 4 speakers only connecting one at a time. You will probably find that either a speaker has gone bad or the speaker wiring has gotten chaffed or pinched. If it still turns on and off I would say the output transistors in you amp are fried. I believe that Kenwood has a 3 year warranty on their amps, if I remember right. Good luck!!!