Tuesday, October 27, 2015

NORCENT and AOC - LT2725 LCD TV - SERVICE MODE - POWER and AUDIO OUTPUT CIRCUIT DIAGRAM

How to enter Service mode [Factory Mode] to AOC LT2725 and Norcent LT2725 LCD TV - SMPS and Audio Output Schematics - Adjustments - Password reset - Parental Control Adjustments.
Used ICs: TC2001 - TP2050 – HJM2199 – STR-A6252 – SI-8120 – FP130
To set or change the password
Enter the old password and then enter the new password.
Confirm new password.
The default password is: 0000
Parental control
Before enter the parental control menu, key in the password first.  The user can set the restricted table about MPAA or TV rating separately.
The default password is: 0000
Press the EXIT button to exit from this adjustment mode.   
SMPS [Power supply Regulator Board] Circuit Diagram
Audio Output Section Circuit Diagram
Factory mode [Service Mode]
In the TV mode adjust volume to zero and press number key 9  8  7  6.
It will achieve the factory mode. Select the item of White Balance and press right key to enter it.
White balance adjustment
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 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. colour temperature select: Cool, Normal, and Warm.
Gain adjustment
A. Adjust Cold colour-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 colour temp is in SPEC. or not.
10. Enter the 8 item to select another colour temperature to adjust.
B. Adjust Normal colour-temperature
1. Set the Contrast of OSD function to 80 and Adjust Brightness to chroma-7120 Y>350cd/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>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 colour temp is in SPEC. or not.
10. Enter the 8 item to select another color temperature to adjust.
C. Adjust Warm colour-temperature
1. Set the Contrast of OSD function to 80 and Adjust Brightness to chroma-7120 Y>350cd/m2
2. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
3. Switch the MEM. channel to Channel 04 (with up or down arrow on chroma-7120)
4. The LCD-indicator on chroma-7120 will show x =308, y =324, 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 colour temp is in SPEC. or not.
10. Enter the 8 item to select another colour temperature to adjust.
Switch different source
Press the source key on the remote control to switch different source to adjust the AV, HDMI, CONPONENT 480i
and COMPONENT 480p mode.
Press “Exit” button on remote control to quit from factory mode.