Drive belts Sony FH-B411

You may have an issue with the cassette deck on your Sony LBT-D550. The cassette deck uses a belt drive system to operate the cassette mechanism; if belts are broken, it can cause the deck to malfunction.
All the belts may have failed at the same time, but it's also possible that there is another issue causing the problem. Some possible causes of a cassette deck malfunction include:

• A problem with the cassette mechanism itself, such as a jammed cassette or worn-out gears.
• A problem with the cassette deck's motor, which a malfunctioning capacitor or other components could cause.
• A problem with the cassette deck's control board, which a malfunctioning switch or other components could cause.

To determine the cause of the problem, a professional technician should look at the cassette deck.

All you need to do is measure the diameter of each belt in MM. Then put "Cassette drive belt ??mm" into Google and you should find a supplier. Belts are not generally specific to any maker. Also you don't need to be precise on the MM. If you are removing them to measure, make a note of how they fit first.

Chances are it will be the belts which will be either worn or loose. To replace them make a note of how the fit, take photos if that helps. Once off measure the diameter in mm (you don't need to be spot on with it). Then enter "Cassette drive belt ??mm" into google.

Fault with the drive belts, remove rear covers and take sample belt to buy and replace. Might be difficult to get them but in old stocks.

You should be able to purchase a drive belt for your dech at the link http://promotions.partstore.com/Brand-Landing-Pages/Sony/Sony-E.html?s=google&gclid=CNCokb6YwJsCFQebnAodin0wBA

just go to a good electronics store i bought a pack of ten assorted belts today for $7.97 at **** Smith Electronics

Unit may have defective idler or gear. Have serviced

i had the same problem of not opening the cassette doors and not running with my sony tc wr535. After I repaced the belts myself with new ones it did run fine! :-) An original sony(!) rubber belt set for the two decks costed me 23 euroos incl pp.

http://www.eserviceinfo.com/index.php?what=search2

I am having the same problem with a Sony K717 ES. I found
this site above where they have the service manual for every tape cassette known to man. They ask that you make a donation to
a charity and then they will email you the pdf for free.