Sunday, March 06, 2016

AOC EN7220 – 17 inch LCD monitor – Circuit Diagram – Service mode – Adjustments.

Factory Mode – Adjustments – SMPS, Scaler and Back-light inverter Schematic – AOC EN7220 LCD Monitor.
White-Balance, Luminance adjustment
Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment. Before started adjust white balance, set the Chroma-7120 MEM. channel 1 to 6500 color, MEM. channel 2 to 7800 color ( our 6500 parameter is x = 313 ±10, y = 329 ±10, Y = 200 ±10 cd/m2 , 7200 parameter is x = 296 ±10, y = 311 ±10, Y = 200 ±10 cd/m2) How to setting MEM.channel you can reference to chroma 7120 user guide or simple use “ SC” key and “ NEXT” key to modify xyY value and use “ID” key to modify the TEXT description Following is the procedure to do white-balance adjust.
Press MENU button during 2 seconds along with press Power button will activate the factory mode, then MCU will do AUTO LEVEL automatically. Meanwhile press MENU the OSD screen will be located at left top of panel.
Bias adjustment 
1. Set the contrast to 70.
2. Sdjust the Brightness to 90.
Gain adjustment
Move cursor to “-Factory-” and press MENU key a. Adjust 6500 color-temperature
1 Switch the chroma-7120 to RGB-mode (with press “MODE” button )
2 switch the MEM. Channel to Channel 01 ( with up or down arrow on chroma 7120 )
3 The LCD-indicator on chroma 7120 will show x = 313 ±10, y = 329 ±10, Y = 200 ±5 cd/m2
4 Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100
5 adjust the GREEN on OSD, until chroma 7120 indicator reached G=100
6 adjust the BLUE on OSD, until chroma 7120 indicator reached B=100
7 repeat above procedure ( item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2
8 Press Exit on OSD window to save the adjustment result.
Adjust 7800 color-temperature
9 Switch the chroma-7120 to RGB-mode (with press “MODE” button )
10 switch the MEM.channel to Channel 02 ( with up or down arrow on chroma 7120 )
11 The LCD-indicator on chroma 7120 will show x = 296 ±10, y = 311 ±10, Y = 200 ±5 cd/m2
12 Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100
13 adjust the GREEN on OSD, until chroma 7120 indicator reached G=100
14 adjust the BLUE on OSD, until chroma 7120 indicator reached B=100
15 repeat above procedure ( item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2
16 Press Exit on OSD window to save the adjustment result. 
Turn the POWER-button off to on to quit from factory mode.
CIRCUIT DIAGRAM
SMPS
BACK-LIGHT INVERTER

SCALER
EDID Content
D-SUB Connector (Analog)
Note: Byte 0C, 0D, 0E, 0F means Serial No. Byte 10, 11 means Manufacture Time. Byte 7F means checksum.