White Balance (Market Mode Chk 3) - Panasonic TX-25P20T Service Manual

5.1.

White Balance (MARKET MODE CHK 3)

5.1.1. Preparation
1. Receive a colour bar signal with colour "OFF", and operate
the TV set for more than 15 minutes.
2. Set the picture menu to "DYNAMIC NORMAL" and the AI to
off.
3. Connect an oscilloscope to TPL7 with DC mode.
4. Set the TV set to Market Mode : white balance adjustment
(CHK 3).
5. Set the data level of SUB BRIGHT, R,G,B-CUT OFF and
R,G,B-DRIV to the table values.
Display
R-CUT OFF
G-CUT OFF
B-CUT OFF
R-DRIVE
B-DRIVE
SUB BRIGHT
5.1.2. Adjustment
1. Select G-CUT OFF adjustment mode and collapse vertical
scan.
2. Adjust G-CUT OFF control to become the DC=0V to video
level at 180 V as shown in Fig. 1.
3. Slowly turn the screen control clockwise until a green colour
horizontal line appears on the picture tube. This is the
setting point for the screen control.
Note that do not adjust the G-CUT OFF setting in the
following procedure.
4. Adjust the remained R and B-CUT OFF contyrols so as to
get a white horizontal line on the screen.
5. Return to full SCAN by pushing the position 5 key on the
remote control.
6. Adjust the R-Drive and B-Drive controls as to obtain uniform
white on the white bar of the grey scale pattern.
7. Confirm correct B/W rendition and greyscale tracking or
repeat CUT OFF and drive control set up.
Data Level
63
128
63
128
128
63
Note : Write down the original value for each address
before adjusting anything.
8. Wedge A shown in Fig. 2 should be fixed within a range of
45 to the left of the vertical line as shown.
9. After inserting wedge A, insert wedges B, C and D. The
wedges should be set 90 degrees apart from each other.
10. Be certain that the four wedges are firmly fixed and the
Deflection Yoke is tightly clamped in place otherwise the
Deflection Yoke may shift its position and cause a loss of
convergence and purity.
5.1.3. Adjustment of Pincushion
1. Receive the crosshatch pattern.
2. Adjust the vertical line to straight line by PARABOLA.
3. Adjust the vertical line to straight line of bothside vertical
line in Fig. 1 by TRAPEZOID.
4. Adjust the corner-pincushion in Fig. 2 by EW-CORNER 1
and EW-CORNER 2.
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TX-25P20T