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VII. ELECTRICAL ADJUSTMENT
A. Safety precautions
1. It is safe to adjust after using insulating transformer between the power supply line
and chassis input to prevent the risk of electric shock and protect the instrument.
2. Never disconnect leads while the TV receiver is on.
3. Don't short any portion of circuits while power is on.
4. The adjustment must be done by the correct appliances. But this is changeable in
view of productivity.
B.
Adjustment procedure
The chassis of this TV set uses Philips single chip IC with the latest digital bus
processing technology. The adjustment points are fewer and the adjustment is simpler.
The adjustment method is as follows:
1. +B: 127V+-0.5V adjustment
1) Switch on the power and connect PAL circular signals to the modulator.
2) Turn the acceleration pole anticlockwise fully. Adjust potentiometer VR701 until
the voltage of the main power is 127V+-0.5V.
2. Screen voltage adjustment
1) Switch on the power and receive PAL system circular signal. Warm up the TV set
for 15 min.
2) Press factory handset SERVICE button to enter the adjustment status. Press
MENU button twice. After the screen displays MENU3, press button 0 and a horizontal
bright line appear. Adjust screen potentiometer to let the horizontal bright line just
appears.
3.
Focus adjustment
1) Receive electronic circular signal
2) Set contrast control to max.
3) Set brightness control to middle
4) Adjust focus potentiometer F1 and F2 until the optimum picture is achieved
4. AGC adjustment
1) Switch on the power and connect signals to the modulator. Receive PAL system
color bar signals (strength: 60dB)
2) Connect the negative end of the digital display voltmeter to earth and the positive
to TPA of AGC input.
3) Press factory handset button to enter the adjustment status. Press button 6 to
adjust AGCTAK, which is usually set to 0B and the measured voltage value is usually
3.85~4.25V.
5.
White balance adjustment
1) Close the color intensifying function.
2) Enter the factory picture adjustment status and adjust R, G, and B.
3) Coordinate of reference white color: (X=0.281, Y=0.311)
6.
Adjustment of line and frame size
1) Switch on the power and connect the signals to the modulator to receive
PAL/NTSC system circular signal.
2) Press factory handset button to enter the adjustment status. Enter GEOMETRY.
First adjust PHS/NHS until the horizontal center is at the center of the screen. Then
adjust PEW/NEW until the horizontal size is 90~92%. Adjust PSL/NSL, PVS/NVS,
PVA/NVA after PSC/NSC until the vertical size is 90~92%. Try to make the electronic
circle as round as possible and the vertical center in the center of the screen.
7.
Adjustment of pincushion distortion
30
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