A cassette deck, or player, is a platform that allows you add content to a cassette tape that you can playback and enjoy. To allow the information on the film in the cassette to be read, there are wheels that rotate to feed the film past the heads, which play the sound. If these wheels stop turning, you will not hear the tape properly. An old and worn belt within the deck often causes this, as it is the part that make the wheels move. You can replace the belt yourself, but you will need to pay careful attention as you work.
Remove the housing around the cassette player with a small screwdriver until the housing comes free. The number of screws holding the housing in place will vary with each type of cassette deck. Unscrew the cover plate of the deck by removing the screws on the underside. When the screws are removed, you will be able to lift the plate up and away from the player. Place the screws in a secure area.
Disconnect the leads of the circuitry assembly that are connected to the base of the deck. This will allow you to move the assembly and expose the belts. Look at the belt pattern to see how it is wound around the heads in the deck. You will need to place the new belt in the exact same way. Pull the old belt out of the deck. You may cut it with scissors, if necessary.
Place the new belt on top of the deck along the path that it will follow. Push it down into the deck around the heads, according to the pattern of the old belt. You will need to stretch it to get it into place.
Reconnect the circuitry assembly and replace the cover plate. Screw the cover plate back into place with the screws through the underside of the deck.
Put back the housing and screw the pieces in place. Make sure that all of the screws that were removed are placed back into the housing.
Draw a diagram of the circuitry connections and the belt path, if you are not familiar with the inside of your deck, advises AllSands.com.
If the belts of your cassette deck fall off, they are very likely broken or stretched out and you should replace them right away.