If the drive belt on your tape player breaks or becomes badly worn, it will seriously affect the machine's playability and perhaps render it completely useless. It is not too difficult to replace the drive belt, which you can order from your local audio-repair store using your player's model number. This number is usually located on the back panel or on the bottom of your cassette player.
Unplug your tape player. Use a screwdriver to remove all the screws that hold the outer casing onto the device. Carefully remove the casing.
Locate the drive belt, and remove any components obstructing your access to it. Make a note of where these components are located before removing them.
Remove the drive belt by carefully stripping it off the motor and pulleys if it has snapped. Cut it with a pair of scissors and then pull it out if it's still in one piece but badly worn.
Thread the replacement belt around the drive pulley of the motor and over the other pulleys that turn the capstans and cogs. Use a pair of tweezers to help you thread the belt. Gently turn the pulleys to check that the belt is in its correct position.
Reattach any components you removed. Replace the case, and screw in the removed screws. Plug in your tape player.
Never work on a tape player before unplugging it first.