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Service manual-EC5 chassis
B1 POWER SUPPLY ADJUSTMENT
1. Set VR641 to be mechanical centre before pressing
the main switch.
2. Tune the receiver to PAL circular pattern.
3. Set brightness and contrast controls to normal.
4. Connect digital V-meter to the right side terminal of
R638.
5. By using VR631, adjust voltage to 130 ± 0.5 V (for 14
and 21 inch).
By using VR631, adjust voltage to 150 ± 0.5 V (for 25
and 28 inch).
AFT ADJUSTMENT
1. Tune the receiver to the clearest station.
2. By using T141, adjust AFT to obtain the best picture.
AGC ADJUSTMENT
NOTE:
Do not attempt this adjustment with weak
signal.
1. Tune the receiver to the clearest station.
2. Set AGC VR(VR131) in direction which causes snow
noise to appear, then in the opposite direction until
snow noise just disappears.
GREY SCALE ADJUSTMENT
[SCREEN VR ADJUSTMENT]
1. Tune the receiver to the white pattern.
2. Set brightness and contrast controls to normal.
3. Set VR702 and VR712 to be mechanical centre.
4. Turn VR701, VR711 and VR721 fully counter-clock-
wise.
5. Connect a short lead between pin30 of IC801 and
GND to enter the service mode.
6. Set screen VR for one colour to be just visible.
[BIAS VR ADJUSTMENT]
7. By using VR701, VR711 or VR721, adjust line to be
white.
8. Disconnect a short lead.
[DRIVE VR ADJUSTMENT]
9. By using VR701 and VR711, adjust white balance.
HIGH VOLTAGE & WIDTH ADJUSTMENT
[HIGH VOLTAGE ADJUSTMENT]
1. Tune the receiver to circular pattern.
2. Set brightness and contrast controls to maximum.
3. Connect digital V-meter to both terminals of R224, and
high voltage meter to CRT anode.
4. Confirm high voltage to be 21.0 ± 1 KV at beam cur-
rent 0.7mA, and less than 25.0 KV at 0 beam current
(for 14 inch).
Confirm high voltage to be 25.0 ± 1 KV at beam cur-
rent 1.2, and less than 28.0 KV at 0 beam current (for
21 inch).
Confirm high voltage to be 26.0 ± 1 KV at beam cur-
rent 1.3, and less than 29.0 KV at 0 beam current (for
25 inch).
Confirm high voltage to be 26.0 ± 1 KV at beam cur-
rent 1.4, and less than 29.0 KV at 0 beam current (for
28 inch).
[H-WIDTH ADJUSTMENT]
5. If H-width is too wide or narrow, connect or disconnect
a lead wire AD1(for 14 and 21 inch).
Adjust VR462 to obtain proper H- width (for 25 and
28 inch).
6. Reconfirm high voltage.
H-CENTRE ADJUSTMENT
1. Tune the receiver to circular pattern.
2. Adjust H-centre by using VR361.
V-CENTRE ADJUSTMENT
1. Tune the receiver to circular pattern.
2. Adjust V-centre by using SW501.
For 14 inch model, connect or disconnect JS501 to
obtain proper vertical screen centre.
V-SIZE ADJUSTMENT
1. Tune the receiver to circular pattern.
2. Adjust V-size by using VR501.
FOCUS ADJUSTMENT
By using FOCUS VR, adjust focus control for well scan-
ning lines.
