The two spool turntables should move slightly left or right, when FFWD or REW is selected, but the grease on the swivel mechanism below them goes hard and they seize up. If you remove the two turntables, you should see the problem.
Look at the third picture in the first post of this thread:
https://www.vintage-radio.net/forum/...ad.php?t=95280
The deck in that thread is the three speed TD10, but the turntable drive method is the same.