PLAY / RW / FF out of sequence on a HITACHI TRK-8130E

I've just been fixing this Hitachi TRK-8130E
It was fluttering quite a lot so I put a new drive belt on it.
It still fluttered a bit so I cleaned the capstan with alcohol and pinch roller with water- still fluttering.
I let it run on "play" for a couple of hours - still a bit of flutter.
I then came back to it 8 hours later and the flutter had gone.
I don't know if the pinch roller had "rehydrated" and plumped out a bit? Anyway I'm happy to have acheived a fix.

BUT.....
Somehow I have disengaged the correct sequence for PLAY / RW / FF
Like - PLAY works, but RW and FF dont.
I lifted the flywheel and gave the motor rubber wheel a wiggle and then I got FF when I pressed play and no RW.

So somehow I have let it slip into the wrong engagement sequence - any advice on how to get it back to normal??

Looks like the belt isn't fully on white pulley wheel in pic

Doh - it was a tiny spring that had fallen off.
It was the spring that pulls the rubber wheel up into contact with the takeup reels.
All fixed, time to kick out the jams!