Quick note on an interesting issue on a Sharp cassette player. I found this on RT-2251, but may affect other models too.
The unit may have take up wheel not moving, or even fast forward /rewind failing.
The root cause is a rubber sleeve which sits on flywheel spindle, connecting it to the rubber tire and then to take up wheel.
This rubber sleeve melts and spreads all over the mechanism messing almost everything up.
To fix :-
Remove unit and clean it properly removing all the gunk from the rollers.
Remove flywheel and replace the sleeve. You can use insulation from multi meter probe wire as the sleeve, as it fits in well. This is explained here in the video –
Here are some pictures to help someone who is looking to fix it.
Here is the cassette mechanism. You can see the red sleeve on flywheel spindle.This is my replacement not original.
I have used a red sleeve to distinguish it from other parts. I used the insulation from a good quality multi meter probe.
Here is another view –
And here is the backside view. You need to take off flywheel to install the sleeve.
The Problem – This is the original rubber sleeve on the flywheel spindle, which melts, and spreads all over the unit through the tire, causing everything to freeze or misbehave.
Here is my, which is playing perfectly for the past many hours after the fix.
Hope it helps.