Auto Contrast Adjustment; Adc Bias And Gain Control; Panel Brightness Check; Panel Color Check - NEC MultiSync LCD1970NX Service Manual

6. Auto Contrast Adjustment

6.1 ADC Bias and Gain Control

a: Enter the input signal of VESA 640x480 (75Hz) in 8Grayscale+Window+Frame pattern.
Input signal level: 0.7Vp-p
b: OSM into factory mode
c: OSM select to "auto contrast" then press "Left" or "Right" button, then push down key.
d: Press "SELECT" key to auto BIAS and GAIN execute.

6.2 Panel Brightness Check

a: Enter the input signal of VESA 1280x1024 (75Hz) in full white pattern.
Input signal level: 0.7Vp-p
b: OSM setting "brightness" to Max. and "contrast" to 50%.
c: Color temperature setting to "NATIVE" mode.
d: Check the center luminance: 200 cd/m2

6.3 Panel Color Check

a: Enter the input signal of VESA 1280x1024 (75Hz) in full white pattern.
Input signal level: 0.7Vp-p.
b: Color temperature setting to "NATIVE" mode.
c: Check the center color coordination.
x=313 ±30
y=329 ±30

6.4 Color Temperature Check

a: Enter the input signal of VESA 1280x1024 (75Hz) in full white pattern.
Input signal level: 0.7Vp-p.
b: OSM "brightness" setting to MAX (100) and "contrast" setting to 50%.
c: OSM into factory mode, and adjust R, G, B GAIN to meet below color temperature table.
d: Each color temperature SPEC. as below:
Control the color temperature according to the correlation data as follows.
Measurement of correlation data is available only for preset white color 9300K～5000K.
Color Temp.
9300K
8200K
7500K
6500K (sRGB)
5000K
Native
True value
x y
0.283 0.297
0.292 0.307
0.299 0.315
0.313 0.329
0.346 0.359
Native color of LCD panel.
Product check Auto-alignment
Tolerance adjust Tolerance
± 0.011
± 0.011
± 0.011
± 0.011
(2) ∆ E94 < 15
± 0.011
4-11
± 0.005
± 0.005
± 0.005
(1) ± 0.005
± 0.005