Wednesday, December 09, 2015

AOC L32W431 How to enter service mode and power supply circuit

Contents of this article 

  • Service mode 
  • White balance adjustment
  • Circuit digram 

AOC L32W431

ENTER FACTORY
Press 1-9-9-9 on remote to enter the menu on top left of the screen),then from UP key(
UP) option to enter the menu.
White Balance, Luminance Adjustment
Instrument List:
Chroma 2225,
VG848,Chroma 7120
Adjustment Process:
1. Instrument Orientation
Connect LCD-TV,
Chroma 2225 and VG848, and set Timing137,Pattern1 on Chroma2225. Chroma7120’s lens
must aim at the center of Pattern1 showed on the LCD-TV’s screen. The distance of Chroma7120’s lens and the
center of screen is 20cm±1cm.
2. ENTER FACTORY
After orientation OK, set Pattern104(black picture) on Chroma225.Press 1-9-9-9 on remote to enter the menu on
top left of the screen(refer to fig.1,this menu will show slowly), then from UP key(
) option to enter the menu
PC Mode White Balance Adjustment
Begin to adjust the W/B (White Balance) you should select the Color Temp(Warm and Cold) and enter the son menu from father menu “Scaler”.
Set channel color temperature value and brightness on Chroma7120.Set 303 319 350(warm Temp) on CH3 and 278 289 350(cold Temp) on CH4.Press MODE key on Chroma7120 to switch xyY mode. Use black sleeve on Chroma7120’s lens to ensure no external ray. 
Set Pattern104 on Chroma2225.Adjust SCALAR RB,GB,BB value to make sure the brightness is the lowest, then set Pattern105 on Chroma2225 and adjust RG,GG,BG value to make the value displaying on Chroma7120 is about 100.Press “Save” to save. 
Switch to CH4, select cold Temp and then adjust it according to above method. Press “Save” to save.
AV MODE W/B ADJUSTMENT
Begin to adjust AV/COMPONENT YPbPr(480I/576I)/COMPONENT T-scaler(480P/720P/1080I) /HDMI W/B, their Color Temp modes
1.OFFSET(26%) W/B ADJUSTMENT(This is only for AV/TV) Change the input signal to 26% white level performance .Set the CHROMA7120 to 288 301 30 and MODE_RGB ,then adjust the TV’s RB GB BB to make CHROMA7120 display to 100.

2.W/B ADJUSTMENT (100%): Change the input signal to 100% white level performance. Set the CHROMA7120 to 288 301 415 and MODE_RGB , then adjust the TV’s RG,GG,BG to make CHROMA7120 display to 100.

3.Save the adjustment. Then change the input signal to 26% white level performance. Set the CHROMA7120 to MODE_RGB and CH3, check whether the color temperature was in SPEC (color spec is x±15;y±15;Y±15). In this time, most of the TV is in SPEC, while the others should be adjusted twice or more to make its color temperature in SPEC.

4.CHECK CUT OFF: Change the input signal to 0% white level performance. Firstly, press the “brightness” from 50% to 0% and make sure the Y is not changed. Secondly, change the input signal to 32 GRAYS performance and make sure the grays is not connected at any position.( as the 5% level is between the first gray and the second gray. 5%=1/321.6)

1.The white color temperature in PC Mode should be app.7200K(CIE1931: x=0.303, y=0.319 Y>350), 10300K(CIE1931 : x= 0.278, y= 0.289, Y>350 ).

2.The white color temperature in AV/TV Mode should be app. 8700K(CIE1931:x=0.288±15, Y=0.301±15, Y>370). In this Mode,we should check the black balance,which level is 26% of the white level(1.0Vpp).

3. The white color temperature in HDTV/HDMI Mode should be app. 8700K(CIE1931:x=0.288±15, Y=0.301±15, Y>370)
Those three channels should be factory preset and not be possible to be modified. The measurement position is the center of the display(5) at brightness set to center and Contrast set to max. . The tolerance of the color coordinates should be less than ± 0.015.
POWER SUPPLY CIRCUIT 
CLICK ON THE IMAGE TO ZOOM IN