Yamaha K-600 Low Level Hum

[ejman]

I have a great sounding Yamaha K-600 cassette deck with a low level 60 hz hum that I can not get rid of. The hum is only there when the cassette is playing (no hum with the unit on but cassette stopped). Runing a ground wire to the deck , reversing the plug and changing RCA's don't help.

Any ideas? :scratch2:

[BrocLuno]

It may be a Cap, transistor or a chip in the Mute circuit. I have two Sonys doing the same thing. One is at Fred Longworths getting fixed. You need the service manual and the troubleshooting guide. A scope helps to track it down.