Phonoland

I have a Seeburg Q100. Recently, I've noticed that the pitch of he music being played seems to vary. It sounds like what we used to call turntable "wow" in the good old days of Hi-Fi. I thought it was due to warped or off-center records, but when I play the same records on a turntable, they sound fine. It sounds worse with slow songs. What might be happening to the drive system that could cause this?

Many things--Assuming you are speaking of 45rpm records only--electrically, a bad motor condenser ( not common), failure of the "P" contacts to open. Mechanically, lack of proper lubrication, worn bearings, worn and/or poor thrust bearing adjustments. The needle brush (or anything else) hitting the record's edge. Clamp arm failing to hold tight. Can't think of more at the moment.
Ron Rich