ViewSonic VA721 – 17 inch TFT LCD display – Color monitor - service mode – adjustments – Power and inverter circuit diagram

How to enter service mode – Viewsonic 17 inch TFT LCD color monitor – service mode adjustments – Power, Inverter, scaler and MCU schematic

Service mode (Factory mode)
Power turn off, Press“▲” and “2”and turn on power at the same time after power LED is on, release “▲ ”and“2” key.
Then press “1” key go to factory mode.

Adjust Color Temperature:
(1) EEPROM INIT (5 BLOCKS):
(1) Press “▼” key move cursor to EEPROM INIT, Press’2’ key then monitor will INIT ADC value.
(2) Press “▲” key move cursor to “White Balance”, Press’2’ key do white balance adjustment.
(3) Press “▼” key move cursor to “Color Temerature Adjust”, Press’2’ key, The OSD will display.
(4) 9300K verify: move cursor to 9300K Press ‘2’key.
Press “▼ ” ,“▲ ” key adjust R.G.B value
x=0.283 ±0.02
y=0.298 ±0.02
Press"1" key return

         Click on the pictures to Magnify 

SMPS schematic

Scaler schematic

Inverter

MCU

(5) 6500K verify: Repeat (4) press “▼” ,“▲ ” move cursor to 6500K press key 2
x=0.313 ±0.02
y=0.329 ±0.02
Y≧ 240 cd/m2
(6) 5400K verify: Repeat (4) press “▼ ” ,“▲ ” move cursor to 5400K press key 2
x=0.332 ±0.02
y=0.348 ±0.02
(7) Press ‘1’ key go back. Then press’1’ key return. 
Power key OFF/ON quit factory mode

G. Color Temperature & Luminance Verify:
BRIGHTNESS MAX, CONTRAST MAX
9300K: x=0.283 ±0.02 y=0.298 ±0.02
6500K: x=0.313 ±0.02 y=0.329 ±0.02 Y≧ 240 cd/㎡
5400K: x=0.332 ±0.02 y=0.348 ±0.02

Geometry
(a). Set cross-hatch pattern and preset timing as timing table listed.
(b). Change to each mode in turn and wait for the monitor finish auto-alignment and save process before change to next mode.
(c). After all of the modes are adjusted, exit OSD menu and press PWR OFF to exit factory mode.