1979
Betamax PVC700



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Technical

The Deck and Heads

When a tape is inserted it is automatically loaded around the head. The video head itself is a 2-pin design and when replaced the new head requires extrencity alignment. The Audio/Control head like the video head is the same as used the Sony SL-C5.

The deck is a cutdown version of that used in the C5. Not so many belts are employed in the NEC model. The capstan is powered by a DC motor and a belt is used to drive the flywheel, the head and the reel drive pulley. Pause is activated by a solenoid pushing back a level on the reel pulley. This makes the operation noisey but it is a smooth and quick action.

Rewind and Fast Forward are activated by a swinging pendulum idler again control via a solenoid.

The counter is belt driven from the take up spool.

The Tuner, Timer and clock

The tuner is a rotary dial type allowing 8 channels to be stored. The RF and tuner circuitary is mostly Sony based although does not look the same as the C5.

Inside the PVC700 The Clock module is a simple 4 digit display. It is NEC in origin but is exactly the same design of tube used in the SLC-5.

Chroma and Audio Boards

These are NEC is design but employ mostly Sony components.

Control features

The control logic is on the left of the power supply.There are seperate pots to allow adjustment of picture search speed etc.

Fault Guide

This is based apon the Sony SL-C5 pages.

Tape transport is sluggish / fails to rewind

Internally the VCR contains many drive belts which are used in the mechanics of tape transport. With age these belts become slack causing malfunctions and when this happens the whole lot should be replaced. In particular for the rewind function you will need to replace a tyre on the supply reel.

Strange behaviour of capstan/drum servo

The first thing to check is the tantalum capacitors in the servo circuit. Look for the 2.2 microfarad ones first.

Sluggish threading and capstan problems

The bottom bearing on the capsten motor is prone to wear and because this motor also drives the threading mechanism threading can become sluggish. When this happens you will hear a horrible squeaking noise! It is possible to strip down the motor and replace the bearing but an easier option is to replace the entire motor if you can find a replacement.

Quick fault guide

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Technical centre

Many thanks to James Copp-Taylor [email protected] for providing information and pictures of this model.

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