Loaded or unloaded? Record on the platter with stylus tracking in the grove?
Have you ever checked the speed before for the correct speed?
Is the motor an AC synchronous type motor?
http://en.wikipedia.org/wiki/Synchronous_motor
Mains frequency could be higher than 60Hz.
If this is the first time you have ever checked the speed I would think other factors could be the reason the speed is off other than the motor.
Tolerance specs in the manufacturing diameter of the motor pulley or platter.
I would think the way the belt rides in the pulley grove.
Have you ever checked the speed before for the correct speed?
Is the motor an AC synchronous type motor?
http://en.wikipedia.org/wiki/Synchronous_motor
Mains frequency could be higher than 60Hz.
If this is the first time you have ever checked the speed I would think other factors could be the reason the speed is off other than the motor.
Tolerance specs in the manufacturing diameter of the motor pulley or platter.
I would think the way the belt rides in the pulley grove.

