RCA L15D20, AOC 1255A LD7552BiCOMS SMPS CIRCUIT DIAGRA - 15 inch LCD TV – How to enter the service mode,Service mode, white balance adjustments and more Remote control part number: R130D1

White Balance, Luminance Adjustment 
Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment.
First adjust PC mode and then adjust AV mode, HDMI mode, component 480i mode, component 480p mode. Before started adjust white balance, please set the Chroma-7120 MEM. Channel 01 to Cold color MEM. and channel 03 to Normal color, MEM. and channel 04 to warm color, MEM.(cold parameter is x = 289, y =304; normal parameter is x =299, y =315; warm parameter is x =313, y =329 )
Note: The tolerance of the color coordinates should be less than ± 20.
How to setting MEM. channel you can reference to Chroma-7120 user guide or simple use “ SC” key and “ NEXT” key to modify x, y , Y value and use “ID” key to modify the TEXT description
Following is the procedure to do white-balance adjust.
Note: Step of AV, HDMI, COMPONENT480i, COMPONENT480p mode adjustment is the same as PC mode,
PC mode:
Ⅰ. In the TV mode adjust volume to zero and press number key 9> 8> 7> 6.
It will achieve the factory mode [Service Mode].
Select the item of White Balance and press right key to enter it.
In the White Balance you can adjust 8 items.
1-3 items is RO, GO, BO  R, G, B Bias adjust.
4-6 items is RG, GG, BG  R, G, B Gain adjust.
7 item needn’t adjust
8 items is color temperature select: Cool, Normal, and Warm.
Bias (Low luminance) adjustment
1. Set the raster pattern (Black pattern with 1024×768) Input.
2. Adjust the brightness on OSD until chroma 7120 measurement reach the lowest value.
Gain adjustment
A. Adjust Cold color-temperature:
1. Set the Contrast of OSD function to 80 and Adjust Brightness to chroma-7120 Y>180 cd/m2
2. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
3. Switch the MEM. channel to Channel 01 (with up or down arrow on chroma-7120)
4. The LCD-indicator on chroma-7120 will show x =289, y =304, Y>180cd/m2
5. Adjust the 4 item: RG, until chroma 7120 indicator reached the value R=100
6. Adjust the 5 item: GG, until chroma-7120 indicator reached the value G=100
7. Adjust the 6 item: BG, until chroma-7120 indicator reached the value B=100
8. Repeat above procedure until chroma-7120 RGB value meet the tolerance =100±2
9. Switch the chroma-7120 to x, y, Y mode with press “MODE” button to check the color temp is in SPEC. or not.
10. Enter the 8 item to select another color temperature to adjust.
LVDS  schematic
Adjust Normal color-temperature
1. Set the Contrast of OSD function to 80 and Adjust Brightness to chroma-7120 Y>180cd/m2
2. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
3. Switch the MEM. channel to Channel 03 (with up or down arrow on chroma-7120)
4. The LCD-indicator on chroma-7120 will show x =299, y =315, Y>180cd/m2
5. Adjust the 4 item: RG, until chroma 7120 indicator reached the value R=100
6. Adjust the 5 item: GG, until chroma-7120 indicator reached the value G=100
7. Adjust the 6 item: BG, until chroma-7120 indicator reached the value B=100
8. Repeat above procedure until chroma-7120 RGB value meet the tolerance =100±2
9. Switch the chroma-7120 to x, y, Y mode with press “MODE” button to check the color temp is in SPEC. or not.
10. Enter the 8 item to select another color temperature to adjust.