Fault and repair guide
Tape transport is sluggish or fails to rewindInternally 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 servoThe 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 problemsThe 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 searchAlthough the C5 did not support colour in picture search it is possible to obtain colour by removing the colour mute transistor!
Camera SocketThe 14 Pin Camera socket is known as a Sony K-connector. Details of the pin connections are available online.
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|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|
|Major loss of sync in playback||Replace these light blue Sanyo caps on AS-6 servo board with tantalums, 25 WVDC or higher. Board is accessed via the underside of enclosure by removing cadmium-coloured screws at board perimeter and 2 in the middle.
C041 0.33 / 25V
C043 1.00 / 25V
C011 0.47 / 25V
C045 0.47 / 25V
C052 0.22 / 25V
thanks to steptoesyard on www.vintage-radio.net/forum