XOCECO LC20H3D, Service Manual

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5. Adjustment for the TV board
Connect the main board and infrared receiving board (as per wiring diagram 203-L15H30-01JL) and
press the POWER key on the remote control set. Now the indication lamp of the infrared receiving board
is blue or yellow. Measure N301 PIN2 of TV board to be 3.3 V, one terminal of inductor L630 to be 5 V
and one terminal of inductor L632 to be 12 V
6.Adjustment of white balance (using the white balancer CA210 and K7253 signal generator specialized
for LCD)
a).Install the whole TV set
b).Enter the factory menu and perform”PW1306 reset”
c).Exit from the factory menu. Press “signal source” key and enter YPbPr .
d).Input YpbPr signal: 640x480p 60Hz (K7253).
e).Enter the user menu. Set the brightness to 50 and contrast to 50. Press “factory” key to enter the
factory menu, perform “ADC calibration”, input signals of “black field”(EMPT),”white
field”(White-(100%))”fully red”(Full_Magenta)respectively and then calibrate three times.
f).Input signal of “eight grade gray”(Gray(H)-8 ). Use CA-210 to measure the sixth grade and adjust
the brightness and contrast so that Y is around 180. Enter factory menu and adjust the green color
temperature and blue color temperature so that x=270,y=283(red color temperature is constant as128).
g).Exit from the factory menu and enter route RGB. Input 60Hz “pane signal ” (C_Hat_16x12(W))
through port VGA. Enter the user menu and adjust the brightness to 50 and contrast to 50. Adjust the
line center and the field center so that the picture is correctly positioned.
h).Input signal of “16 gray grades” (Gray(H)-16). Enter the factory menu and perform “calibration of
ADC”.
i).Exit from the factory menu, input the signal of “eight grade gray” (Gray(H)-8 )and enter the user
menu. Adjust the brightness and contrast. Use CA-210 to measure the sixth grade so that Y is around
180. Enter the factory menu and adjust the green color temperature and blue color temperature so that
x=284,y=299(red color temperature is constant as128).
j).Enter the factory menu and adjust the green color temperature and blue color temperature so that
x=284,y=299.
Notice: For the best discrimination rate of LCD screen, see table 1.
Table 1:LCD resolution of best
Screen size Factory LCD resolution of best
Samsung
AU
Sanyo
15”
CPT
1024x768
Samsung
17”
AU
1280x1024
AU 800x600
Chimei
20”
LG
640x480
7.Performance check
a).TV Interfaces
Connect RF port to central signal source. Enter station search menu - auto station search. After
system adjustment is over, check if there is any station missing and then check semi-auto station search.