Betamax PALsite: SL-C5 : Technical

SL-C5

1978

Technical

Fault and repair guide

Tape transport is sluggish or fails to rewind

Internally the C5 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. A 'rewind' kit of replacement parts is available from many sources. The Sony part number is A 670634A.

Strange behaviour of capstan/drum servo

The first thing to check is the tantalum capacitors in the servo circuit. Look for the 2.2 micro farad ones first. It is also recommended to replace the light blue electrolytics on the servo board.

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.

Colour in picture search

Although the C5 did not support colour in picture search it is possible to obtain colour by removing the colour mute transistor!

Quick fault guide

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Fault Solution

Blank raster and muted playback with own recordings. Check the audio/control track head for contamination and wear if ok then check the control head replay amplifier for failure.

Intermittently crackling sound. Suspect poor contacts in the audio switching relays.

Intermittently fast forwards in playback. Suspect failure of sensor IC BX3421

Loss of capstan servo lock with noise bars & wow on sound. Try slight adjustment of the capstan free run speed

No/poor sound. Check the setting/condition of preset RV403

No drum rotation. Check diode Dl on the audio/servo board AS6 for short circuit, if fault persists check IC1 ICX1861 for failure.

No play or fast forward. Check capacitors C2, C3 & C4 for failure

No sound in e-e mode or record. Suspect failure of the sound IF chip IC503 [TBA2OB]

Poor picture with horizontal blue lines down screen. Check the tape back tension and the positioning of the tape path guides before suspecting the heads of wear failure

Shuts down when play is initiated but LED remains lit. Check the slack sensor lever and the reed switch

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Technical centre

Camera Socket

The 14 Pin Camera socket is known as a Sony K-connector. Details of the pin connections are available online.

Fault	Solution
Blank raster and muted playback with own recordings.	Check the audio/control track head for contamination and wear if ok then check the control head replay amplifier for failure.
Intermittently crackling sound.	Suspect poor contacts in the audio switching relays.
Intermittently fast forwards in playback.	Suspect failure of sensor IC BX3421
Loss of capstan servo lock with noise bars & wow on sound.	Try slight adjustment of the capstan free run speed
No/poor sound.	Check the setting/condition of preset RV403
No drum rotation.	Check diode Dl on the audio/servo board AS6 for short circuit, if fault persists check IC1 ICX1861 for failure.
No play or fast forward.	Check capacitors C2, C3 & C4 for failure
No sound in e-e mode or record.	Suspect failure of the sound IF chip IC503 [TBA2OB]
Poor picture with horizontal blue lines down screen.	Check the tape back tension and the positioning of the tape path guides before suspecting the heads of wear failure
Shuts down when play is initiated but LED remains lit.	Check the slack sensor lever and the reed switch
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