I usually repair guitar amplifiers. But I've been getting into repairing vintage receivers and other devises. I'm self taught and have been doing pretty good so far. I just repaired a Harman Kardon PM660. Well, repaired it for the most part. I had to replace a couple output transistors, a driver transistor and a couple 1/4 watt resistors. It's out in my shop playing right now and sounds great. But sometimes you turn it on and it doesn't work. I get a periodic pop like a breaker is kicking on and off. I play with it a bit and turned it off, let it sit a minute and it started working again. And as I said it's sounds fine. Been playing for about 20 minutes now.
Anyone have any ideas what might be causing this problem? I don't want to give it back to the owner and have this happen to him. The speaker impedance is correct. Thanks in advance.
Anyone have any ideas what might be causing this problem? I don't want to give it back to the owner and have this happen to him. The speaker impedance is correct. Thanks in advance.