White Balance, Luminance Adjustment - Norcent LT2725 Service Manual

27'' LCD TV Color Monitor

6. 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.(Our cold parameter is x = 291, y =306; normal parameter
is x =299, y =315; warm parameter is x =308, y =325)
Color Temp.
PC MODE
AV MODE
HDMI
COMPONENT
（480i/480p）
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
factory 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
4-6 items is RG, GG, BG
7 item needn't adjust
8 items is color temperature select: Cool, Normal, and Warm.
Ⅱ. 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.
Ⅲ. Gain adjustment:
A. Adjust Cold color-temperature:
1. Set the Contrast of OSD function to 80 and Adjust Brightness to chroma-7120 Y>350 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 =291, y =306, Y>350cd/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.
Cold
x 291
y 306
Y 350
x 291
y 306
Y 450
x 291
y 306
Y 420
x 291
y 306
Y 450
R, G, B Bias adjust.
R, G, B Gain adjust.
25
Norcent LT2725
Normal Warm
299 308
315 325
350 350
299 308
315 325
450 450
299 308
315 325
420 420
299 308
315 325
450 450
8 7 6. It will achieve the