Philips 20MC4304, Service Manual

Page: 109 / 316

1-9-6 T1006EA
7. White Balance Adjustment
Purpose: To mix red, green and blue beams correctly
for pure white.
Symptom of Misadjustment: White becomes bluish
or reddish.
Note: Use service remote control unit
1. Operate the unit more than 20 minutes.
2. Face the unit to the east. Degauss the CRT using
a degaussing coil.
3. Input the White Raster (APL 100%).
4. Set the color analyzer to the CHROMA mode and
after zero point calibration, bring the optical recep-
tor to the center on the tube surface (CRT).
5. Enter the Service mode. Press "VOL
p
" button on
the service remote control unit and select "C/D"
mode. (Display changes "C/D" and "7F" cyclically
when "VOL
p
" button is pressed.)
6. Press "4" button on the service remote control unit
for Red adjustment. Press "5" button on the service
remote control unit for Blue adjustment.
7. In each color mode, press "CH
o
/
p
" button to ad-
just the values of color.
8. Adjust Red and Blue color so that the temperature
becomes 9200K (x: 286 / y: 294) ±3%.
9. At this time, re-check that horizontal line is white. If
not, re-adjust Cut-off Adjustment until the horizon-
tal line becomes pure white.
10. Turn off and on again to return to normal mode. Re-
ceive APL 100% white signal and confirm that Chro-
ma temperatures become 9200K (x: 286 / y: 294)
±3%.
Note: Confirm that Cut Off Adj. is correct after this
adjustment, and attempt Cut Off Adj. if needed.
8. Sub-Brightness Adjustment
Purpose: To get proper brightness.
Symptom of Misadjustment: If Sub-Brightness is
incorrect, proper brightness cannot be obtained by
adjusting the Brightness Control.
Note: SMPTE Setup level --- 7.5 IRE
1. Enter the Service mode. (See page 1-9-1.)
Then input SMPTE signal from RF input.
2. Press "PICTURE" button. (Press "PICTURE" but-
ton then display will change BRT, CNT, COL, TNT,
and V-TNT). Select BRT and press "CH
o
/
p
" but-
tons so that the bar is just visible (See above fig-
ure).
3. Turn the power off and on again.
Test Point Adj. Point Mode Input
Screen
CH
o
/
p
buttons
RF
White Raster
(APL 100%)
Tape M. EQ. Spec.
---
Pattern
Generator,
Color analyzer
See below
Figure
Color Analyzer
Fig. 6
Test point Adj. Point Mode Input
---
CH
o
/
p
buttons
---
SMPTE
7.5IRE
Tape M. EQ. Spec.
---
Pattern
Generator
See below
Figure
Black
White
This bar
just
visible
Fig. 7