I recently acquired a Sansui quadraphonic turntable, model FR-3080. Most of the time when I play an LP, it plays way too slow. Then I'll come back a few hours later and it will play at the correct speed. The next time it will be back to playing extremely slow. I replaced the belt thinking that might help, but no difference. Any suggestions appreciated. This would make a great addition to my quad system if I can get it working properly.

I recently acquired a Sansui quadraphonic turntable, model FR-3080. Most of the time when I play an LP, it plays way too slow. Then I'll come back a few hours later and it will play at the correct speed. The next time it will be back to playing extremely slow. I replaced the belt thinking that might help, but no difference. Any suggestions appreciated. This would make a great addition to my quad system if I can get it working properly.
If it has variable pitch controls you need to open up the turntable and spray DeOxit on the innards of those controls and of the 33/45 selector switch if it is an actual electrical switch and not just a lever that changes belt position.

Also check the motor bearings, clean and re-oil them.

Have you oiled it?