Have a vintage T60 turntable from Harmon Kardon, original owner. This unit has a quartz lock button for the speed, and you can also turn it off and manually adjust the speed. With the quarts lock enabled the speed is slow, maybe 32-1/2 instead of 33-1/3. The service manual indicates this condition would call for a new motor pulley for the belt drive. Seems like a weird fix. Anyone familiar with this unit, and ever resolve this issue? Obviously the motor pulleys are no longer available.
A friend said try replacing the power supply caps as older caps can mess with the signal for the motor.