Marantz 6300 tt problem

Hello everybody. I am having a problem with my 6300. The motor is not spinning at a constant speed. I tried another motor and it does the same thing. It seems to go on and off. Cleaned up the pitch potentiometers and then changed them and same problem shows up. The strobe light stays on with no problem. I touched one of the pitch control pot.with a screwdriver and the motor starts to work fine. It is driving me crazy. Checked all the connections and they are fine. Could it be a bad transistor? I also changed the switch for the 33/45 speed
Any help will be greatly appreciated
Thank you

have you cleaned the pitch preset controls inside the motor yet?

The speed selector switches go bad. Sometimes you can resurrect them with deoxit by squirting inside and working the switches. Same can be said for the on/off switches.

There is also a .22 microfarad bypass cap in the motor circuit (small blue electrolytic soldered between two posts on the board) that gets leaky and causes speed instability.


Cheers!