MITSUI MTV-DV05, Service Manual

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SERVICE MANUAL
CIRCUIT ADJUSTMENTS
Preparation:
Circuit adjustments should be made only after completion of set-up adjustments.
Circuit adjustments can be performed using the adjustable components inside the TV set. For TVs with
I
2
C bus control, first change the bus data.
1. Degaussing
A degaussing coil is built inside he TV set. Each time the TV is powered on, the degaussing coil will
automatically degauss the TV. If the TV is magnetized by external strong magnetic field, causing color
spot on the screen, use a specific degausser to demagnetize the TV in the following ways. Otherwise,
color distortion will be exist on the screen.
1.1 Power on the TV set and operate it for at least 15 minutes.
1.2 Receive red full-field pattern.
1.3 Power on the specific degausser and face it to the TV screen.
1.4 Turn on the degausser. Slowly move it around the screen and slowly take it away from the TV.
1.5 Repeat the above steps until the TV is degaussed completely.
2. Supply Voltage Adjustment
Caution: +B voltage has close relation to high voltage. To prevent X-ray radiation, set +B voltage
to the rated voltage.
2.1 Make sure that the supply voltage is within the range of the rated value.
2.2 Connect a digital voltmeter to the +B voltage output terminal VD891 of the TV set. Power on the TV and
set the brightness and sub-brightness to minimum.
2.3 Regulate voltage adjustment components on the power PCB to make the voltmeter read 115
±
1V .
3. High Voltage Inspection
Caution: No high voltage adjustment components inside the chassis. Please perform high
voltage inspection in the following ways.
3.1 Connect a precise static high voltmeter to the second anode (inside the high voltage cap) of the picture
tube.
3.2 Plug in the supply socket (120V, AC) and turn on the TV. Set the brightness and contrast to minimum (0
μ
A).
3.3 The high voltage reading should be less than the EHT limitation.
3.4 Change the brightness from minimum to maximum, and ensure high voltage not beyond the limitation in
any case.
Nominal EHT voltage:
22
±
1KV Limited EHT voltage: 25KV
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