SL-T7
Sony 1979
Betamax SL-T7



beta vcr logo

Technical

SL-T7 rear view
Rear view

SL-T7 inside
Inside

Fault and repair guide

Tape transport is sluggish or 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.

Sluggish threading and capstan problems

The bottom bearing on the capstan 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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FaultSolution
Wega equivilent modelThis is identical to the WEGA Video7 multi standard machine (sold in Middle East). Also see repair notes for C5/C7 as most of the guts are the same/simmilar.
Clock batteryThere are an NiCd battery behind the clock display. Originally intended to keep the time in the case of power faults. Now, 34 years after the production date, it is leaky. Better to replace, or simply remove, before the battery acid damages the PCB.
Red LED on Clock no Power onThe Green LED Off Only Red LED on Clock - Replace the following parts:
There are:
Two transistors broken (NEC-C2335)
Two capacitors (4.7/350v) and (47/16v)
One Resistor (3w 3.3Ωk)
Another Solution For Red LED on Clock no Power onThe Green LED Off Only Red LED on Clock - Replace The Following Parts:
There are:
Two Transistors Broken (NEC-C2335)
IC Power (TL494CN) The same is (GL494)