Betamax PALsite: SL-F90 : Technical

SL-F90

1985

Technical

Fault and repair guide

Stops in play or record

The first thing to check is that there is adequate torque on the take up spool. If there isn't much then the cause is usually down to two contributing factors.

The first is the drive pendulum which can cease up and the second, and the second more serious factor, is wear on the reel motor bottom bearing. The pendulum is simple to replace but the bearing is moulded into the chassis and replacement necessitates that the entire chassis be replaced. One possible compromise is to fit a small piece of plastic into the bottom bearing to raise the rotor and allow it to move freely. Sony supply a repair kit for this purpose.
The diagram above shows the pendulum assembly

No head drum rotation

You may find that the head drum fails to rotate. This is due to a problem with the Hall effect device on the head drum motor which is secured by a blob of glue which tends to become conductive especially if it absorbs moisture. The best remedy is to remove the glue from the device. To do this first remove the rotor from the bottom of the drum by undoing the lock-nut. Sometimes, however, it is enough to wait for the damp to dry out.

Deck goes into rewind

This can be caused by failure of the tape end sensor. You can check this by unplugging the sensor at its socket on the PCB.

Failure to load a tape

The cassette carriage can fail to operate. This is caused by breakage of the plastic gears in the side of the mechanism. When this happens they have to be replaced.

Quick fault guide

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Fault Solution

rfu-857 1-454-690-11
6g26ma

rfu-857 1-454-690-11
6g26ma

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