I have a Grundig Majestic console with a PE Rex delux turntable. The entire unit operates wonderfully with one exception. The turntable is running approximately 3-4% slow. I’ve replaced the belts and the idler wheel. Any suggestions on additional things to replace and or clean would be greatly appreciated.

Welcome to the ARF Phono forum.

1. Have you done dis-assembly and degreased all
the old grease in the changer ?

2. Have you dis-assembled and cleaned the motor ?
2.a. Have you replaced the old motor mount grommets,
if there are any ?

3. Did you cleaned the new idler/belts before installing ?
Did you clean belt pulleys (if any) ?

4. Have you cleaned the inside rim of the record platter ?
4a. Have you removed and cleaned the platter bearings ?

5. Here's the site you can get the manuals for free:
https://www.vinylengine.com/library/per ... luxe.shtml

Hotwax

Do you have the right pulley and idler on it?
is it set to 120V 60 Hz?

Some of those old ones have a 140 V setting in addn to 110/120 and 220/240 so if it's a little anemic that could be why.

Also generally the original German pulley would make it run FAST in the U.S. but I've seen stranger things go on.