Read Sony KV-25C3A Service Manual online
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KV-25C3
3-3. Focus
1. Receive a television broadcast signal.
2. Normalize the picture setting.
3. Adjust the focus control on the flyback transformer for the
2. Normalize the picture setting.
3. Adjust the focus control on the flyback transformer for the
best focus at the center of the screen.
Bring only the center area of the screen into focus,
the magenta-ring appears on the screen. In this case, adjust
the focus to optimize the screen uniformly.
Bring only the center area of the screen into focus,
the magenta-ring appears on the screen. In this case, adjust
the focus to optimize the screen uniformly.
FOCUS
3-4. Screen (G2), White balance
(Adjustment in the service mode with
remote commander)
remote commander)
G2 adjustment (RV3701)
1.
Input a dot signal from the pattern generator.
2.
Set the Picture, Brightness and Colour to minimum.
3.
Apply 170V DC from an external power supply to the
R, G and B cathodes of the CRT.
R, G and B cathodes of the CRT.
4.
While watching the picture, adjust the G2 control
RV3701 [ SCREEN ] on the C board to the point just
before the return lines disappear.
RV3701 [ SCREEN ] on the C board to the point just
before the return lines disappear.
White balance adjustment
1.
Receive an all-white signal.
2.
Enter into the Service Mode by pressing ' TEST ',
' TEST ' and ' MENU' on the Service Commander.
' TEST ' and ' MENU' on the Service Commander.
3.
Select ' VIDEO PROC. ' from the on screen menu display
and press OK .
and press OK .
4.
The ' VIDEO PROC TDA4780' menu will appear on the
screen.
screen.
Video Proc. TDA4780
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5.
Set picture to MAX.
6.
Set the ' R GAIN ' to 25.
7.
Adjust the ' G GAIN ' and ' B GAIN ' so that the white
balance becomes optimum.
balance becomes optimum.
8.
Press the OK button to write the data for each item.
9.
Set picture to MIN.
10. Set the ' R LVL REF ' to 31.
11. Adjust ' G LVL REF ', and ' B LVL REF '
11. Adjust ' G LVL REF ', and ' B LVL REF '
with the left and right buttons so that the white balance
becomes optimum.
becomes optimum.
12. Press the OK button to write the data for each item.
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