Sharp RT-3151 Drive Belt

The Sharp RT-3151 uses a flat drive belt between the motor pulley and huge metal flywheel. To gain access to this part, one has to take the complete tape transport mechanism (TTM) out, and then remove the PCB connected to it. Under the PCB, there is usually a metal plate (not shown here) that secures the metal flywheel, and recording lever, which you also have to remove.

On this unit, the belt had totally perished and required replacing. Unfortunately, flat drive belts tend to be very expensive and I was unable to find a new one that could fit and was at a reasonable cost. However, I always keep recycled spares, and was able to find one that had a good chance of working.

Whilst you are working at this location, it is worth checking and replacing a small rubber pulley in contact with the flywheel edge. This pulley provides the drive to the cogwheels on the other side for the fast-forward and rewind functions. If you find these functions struggling, then cleaning the contact surfaces might help, however the rubber tyre usually requires replacing.

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