VCR UPDATES

V212B, V312B, V412B.
(1) FAULT SYMPTOM - Dead, no display. All power supply output voltages measure half normal voltage, For Example, 14v rail measures 6-7v.
CAUSE - DP15 (ZPD3V9) Zener diode short circuit.
CURE - Replace DP15 3.9v zener diode.
IMPORTANT NOTE - Zener diode DP15 is not shown on the circuit diagram. It is located under RP33 1.5ohm cement wire wound resistor (difficult to see) on the print side of the power supply PCB.

(2) FAULT SYMPTOM - No mechanical operation.
CAUSE - Cam Gear (circuit ref. B710) Jammed and teeth stripped.
CURE - Replace Cam Gear Part No.70011070 (refer to service information for correct assembly and alignment of this part) also replace supply soft brake lever with improved type coloured black included with the replacement Cam Gear.

V212B, V312B, V412B.
(3) FAULT SYMPTOM - Not erasing previous sound track, slight coloured patterning on recorded picture.
CAUSE - Bias oscillator inoperative, this symptom can be very intermittent.
CURE - Although not conclusive, this symptom seems to be cured by improvement in connection between the full width erase head and the connecting cable.
(4) FAULT SYMPTOM - Erasing the sound of pre-recorded tapes and VCR's own recordings.
CAUSE - Bias oscillator still running in play mode, erase off command from micro ok.
CL05 0.01mfd capacitor in base circuit of oscillator open circuit.
CURE - Replace capacitor.
(5) FAULT SYMPTOM - Cassette loads and cylinder spins, but will not play. VCR then goes to standby. Cassette will then eject but tape is not re-loaded into cassette.
CAUSE - +5V supply missing from IT01 logic/servo micro, dry joints at connector BT06, pins 8, 9 and 10.
(6) FAULT SYMPTOM - Slow speed rewind and fast forward.
CAUSE - Power supply not delivering +14v and +18v for capstan at BP03 Pin 3
(UCAPST), +7V only. TP81 and TP83 in power supply both base-collector leaky.
CURE - Replace both transistors type MPS 750 Part No. 70010939 NOTE: surface mounted devices.
(7) FAULT SYMPTOM - Intermittent poor playback (loss of one head) on SP mode, tapping head pre-amp unit can clear fault.
CAUSE - Capacitors CQ05 and/or CQ06 are open circuit (normally cracked). Both of these capacitors are surface mounted components.
CURE - Replace capacitors Part No. 70040991. Wire ended type can be used.

V312B Only
(1 ) FAULT SYMPTOM - When in playback mode, picture continually switches between play and E-E.
CAUSE - Corrupt data control from IT01 servo micro. to IW85 shift register.
CURE - Replace IT01 servo micro part no: 70011398.

V212B, V312B, V412B
With reference to previous bulletin item 3.
FAULT SYMPTOM - Not erasing previous sound track.
CAUSE - Bias oscillator stopped can be intermittent.
If permanent then RL01 10ohm may be O/C and TL01 BC337 S/C.
CURE - a) Fit replacement kit part no: 70903796.
b) Change RT102 from 56k to 39k part no: 24872393
c) Improve connection at full erase head plug and socket by soldering the wires directly to the terminals at the back of the head.
(1) FAULT SYMPTOM - No picture on either E-E or playback.
CAUSE - Shift register IC IW20 MC14094BD faulty.
CURE - Replace IC part no: 70010981.
(2) FAULT SYMPTOM - Slow and jerky to eject tape. Tape gets to front flap, stops then re-loads or may stop during unloading cycle.
CAUSE - Loading motor has dead spots on comutator. Test by removing belt.
CURE - Replace loading motor part no: 70011062
(3) FAULT SYMPTOM - No colour on playback, record colour ok.
CAUSE - Standby 12v from power supply down to 9.6v (DP86 zener diode faulty and RP86 resistor o/c).
CURE - Replace RP86 27ohm resistor part no: 70041074 and DP86 10V zener diode part no:. 70010959.
(4) FAULT SYMPTOM - No sound on E-E or playback and will not stop on station when search tuning.
CAUSE - Audio mute activated due to no vertical sync at pin 31 of IA40.
CURE - Replace vertical sync processing IC IA01 TDA8128 part no: 70010967.
(5) FAULT SYMPTOM - No functions after two minutes goes to standby.
CAUSE - GT22 cam1 photo sensor faulty.
CURE - Replace sensor part no: 70010960.
(6) FAULT SYMPTOM - Power supply tripping after half an hour.
CAUSE - DP08 6.2V zener diode faulty.
CURE - Replace Diode part no: 70010958
(7) FAULT SYMPTOM - Snaps tape in Rew/FF, counter does not work in these modes.
CAUSE - FG output missing from CTL and FG amp IC IT40 pin 15 in FF and Rew.
CURE - Replace IT40 U2565B part no: 70010979

V110B/V210B
(1) FAULT SYMPTOM - Picture pulsates in E-E mode.
CAUSE - XK03 2.4v back-up battery faulty on key display PCB.
CURE - Replace battery part no: 70010166.

V211B
(1) FAULTY SYMPTOM - Will not accept tapes.
CAUSE - IT18 U2561B FG CTL amp IC faulty.
CURE - Replace IC part no: 70010166.

V411B
(1) FAULT SYMPTOM - Intermittent random switching between SP and LP when in Play mode.
CAUSE - PG waveform at pin 11 of IT10 FG CTL amp IC shows superimposed hum signal.
CURE - Replace IT10 U2561B part no. 70010166.

V703B
(1) FAULT SYMPTOM - No test signal. No playback.
CAUSE - Ever 5v missing from Q688 TV/VTR switch and Q685 pre-play +B switch
(circuit protector ZP681 ICP-N5 O/C)
CURE - Replace ZP681 part no: 23118122