A common problem with Sony CD Carousel changers is broken tables on the holders for the support wheels under the turntable. If these holders come loose you they can jam under the carousel and break the fingers used to track the carousel as it spins. (Ask me how I know.)
You should see the tabs from the holders poking through the
bottom of the machine. If they are broken you can easily replace the
holders while you are replacing worn belts with these and keep the carousel
properly supported. When replacing the door belt you have to
remove the carousel anyway, and replacing the wheel supports is very
easy.
I also have replacement wheels available, though these break less often.
You can choose between a set of 5 support wheel holders, 5 wheels only, or 5 wheels and 5 wheel support holders. Your model may not use all 5.
These should work in the following models:
CDP-CX300
CDP-CX335
CDP-CX355
CDP-CX400
CDP-CX450
CDP-CX455
These holders may also be used in the following models but I haven’t been able to confirm it. If you can confirm the models below also use these holders I will give you a 50% discount.
DVP-CX777ES
DVP-CX985V
DVP-CX995V
CDP-M333ES
CDP-M555ES
CDP-CX200
CDP-CX210
CDP-CX220
CDP-CX225
CDP-CX235
CDP-CX240
BDP-CX960
BDP-CX7000ES