LG RD-JT51, Service Manual

Page: 26 / 132

26
III. Gamma Curve:
1. Change Timing and pattern of pattern generator:
Timing: NTSC (H: 15.73 KHz, V: 29.96 Hz)
Pattern: 100% blue
2. Adjust Gamma Index and Red/Green/Blue Gamma to fit mars video gamma
curve.
(B) YPbPr Component:
Equipment:
- Pattern generator (VG-828)
- Lux meter (CL-100)
OSD Default value:
Item Value Item Value
Brightness 0 Brightness Bias Adjustable
Contrast 0 Contrast Bias Adjustable
Filter 1 Pb offset Adjustable
CM-Red-CF1/2 128/128 Pr offset Adjustable
CM-Green-CF1/2 128/128
CM-Blue-CF1/2 128/128
Red Gain 128
Green Gain 128
Blue Gain 128
White Peak 2
Gamma Table Linear
Procedure:
I.
Offset adjustment:
1. Black coordinate spec:
Osram lamp Oshio lamp
X0 0.281 0.01 0.313 0.01
Y0
0.311 0.01 0.329 0.01
2. The variance of color coordinate via Pb offset and Pr offset:
X y
Pb offset x y
Pb offset x y
Pr offset x y
Pr offset x y
3. If we line the x and y, then the Pb offset is the shift action and the Pr offset is
the rotational action.
4. Connect power, YPbPr Video into projector.