Omnivision PVQ-1300W, Service Manual

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of handling 25.0 kV without causing X-Radiation.
NOTE :
It is important to use an accurate periodically calibrated high voltage meter.
1. Reduce the brightness to minimum.
2. Set the SERVICE switch to SERVICE .
3. Measure the High Voltage. The meter reading should indicate 23.5 kV±1.5 kV.
If the meter indication is out of tolerance, immediate service and correction is
required to prevent the possibility of premature component failure.
4. To prevent an X-Radiation possibly, it is essential to use the specified picture tube.
HORIZONTAL OSCILLATOR DISABLE CIRCUIT TEST SERVICE WARNING :
The test must be made as a final check before set is returned to the customer.
CONFIRMATION OF X-RAY MOVEMENT
1. Turn off TV set.
2. Connect the circuit below between TP1209 and TP1208.
Figure 2
3. Turn on DC Power, and then turn on the set. Confirm that the picture is on the
screen properly.
4. Confirm that the picture goes out of horizontal sync while getting down the voltage
to DC Power.
5. If this does not occur even when getting down the voltage of DC Power to 0 V, it
means that X-ray protect circuit is not operating.
Further confirmation and repair is required.
REPAIR PROCEDURES OF HORIZONTAL OSCILLATOR DISABLE CIRCUIT
1. Connect a DC voltmeter between capacitor C513 (+) on the Main circuit board and
chassis ground.
2. If approxi21.9 V is not present at that point when 120 V AC is applied, find
the cause. Check R503, R5505, C5507, C513 and D503.
3. Carefully check above specified parts and related circuits and parts. When the
circuit is repaired, try the horizontal oscillator disable circuit test again.
CIRCUIT EXPLANATION
5