![background image](http://html.mh-extra.com/html/haier/ht-3768/ht-3768_service-manual_138130026.webp)
VII. ELECTRICAL ADJUSTMENT
A. Safety precautions
1. It is safe to adjust after using insulating transformer between the power supply
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 Toshiba 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:
115
±
0.3V adjustment.
1) Switch on the power and connect PAL circular signals to the tuner.
2) Adjust variable resistor RP501 until the voltage of the main power is 115
±
0.3V.
2. Screen voltage adjustment.
1) Switch on the power and receive PAL system circular signal. Warm up the TV set
for 15 min.
2) Enter the adjustment D state. Press the “-/--” button, then a bright horizontal line
appears. Adjust screen potentiometer to let the horizontal line just appears.
3. Focus
adjustment.
1) Receive electronic circular signal.
2)
Set picture mode on standard mode.
3) Adjust focus potentiometer until the optimum picture is achieved.
4.
White balance adjustment.
1) Set the picture mode on standard mode.
2) Enter the D state and adjust RCUT, GCUT, BCUT, GDRV and BDRV.
3) Coordinate of reference white color: (X=0.281, Y=0.311).
6. Adjustment of horizontal and vertical position and size.
1) Switch on the power and connect the signals to the tuner to receive PAL/NTSC
system circular signal.
2) Enter the D state. Adjust HPOS to change the horizontal position and VP50 to
change the vertical position. Adjust HIT to change the vertical size until the
vertical size is 90-92%. Horizontal size is related to the capacitor C416. Hold the
26
Summary of Contents for HT-3768
Page 36: ......
Page 37: ...B Circuit Diagrams 1 ...
Page 38: ...Sincere Forever Haier Group Tel 86 532 8938356 Web site http www haier com ...