Audio Systems: yamaha amp AX-570, sprits, ac line

Question
i have replaced my old amp with the above-mentioned yamaha;the speakers and connections are the same. the sound is great, but sometimes when i switch between "tape 1" (TV) and "tape 2" (tuner)
one speaker will conk out and only emit a faint crackle sound. i can easily rectify the problem by switching back and then reswitching and then the sound comes in fine. would the problem be in the switch and if so how can the problem br rectified?

Answer
you need to get a good control cleaner spray, such as de-ox-id, and open unit so you can see control and give it a small sprits and work control back and forth several times fast to clean contacts of switch. you can spray the volume,tone and any other switches while its open. make sure no ac line power is hooked up when you do this though....hope this helps...