Betamax PALsite: VTC-5150 : Technical

VTC-5150

1982

Technical

Fault and repair guide

No reel rotation

This is a very common problem which can have several causes. The first thing which fails is usually the reel idler assembly. Replacement units are readily available and can be fitted easily after removal of the cassette carriage. Before replacement check for a broken reel motor belt. This is a small belt which transfers drive to the idler. Finally, the last thing to suspect is the reel motor. Sanyo produced a modification to improve drive to this motor. This involved decreasing the value of the in-series resistor in the motor power supply. However, it is not uncommon for the motor itself to fail in which case it needs to be replaced.
The diagram above shows the idler assembly.

No tuner input

This is usually caused by failure of the RF combiner / splitter unit. Unfortunately it is not easy to repair this unit.

12 Hour Clock Display Mod

On the clock PCB there is a position for 12H or 24H clock. Usually they are 24H, but fit a 1N4148 diode in this position (note polarity as per PCB marking) and you get 12H clock with AM/PM illuminated in the display.

Timer and/or standby LED fail to illuminate

This is caused by dry joints where the LED are soldered onto the front PCB. In order to gain access to the PCB you'll need to remove the front panel and the servo board on the LHS of the deck.

Loss of servo lock in record

Recordings can suffer from a loss of drum lock which produces a picture roll and usually occurs between sudden bright/dark transitions. It is caused by problems with the sync separator in the servo circuits, usually due to dried out electrolytic capacitors.

Further Information

For further information on general servicing on this model, take a look at Colin McCormick's excellent guide on How to service a Sanyo Beta.

Colin is also able to supply a service kit for this model.

Quick fault guide

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Fault Solution

Syscon bug VTC5000/VTC5150 Early models of the VTC5150 have been shown to exhibit the same syscon bug as the VTC5000: Failure of reel drive causes machine to lace up and stop. Later versions just stop without laceup, which is clearly better for a machine which has reel drive failure and may not be able to get the tape back into the cassette.

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