Lcd Red Brightness Adjustment - Epson PhotoPC600 Service Manual

5.1.10 LCD Red Brightness Adjustment

Red brightness adjustment is white balance adjustment for Red color. This adjustment is to adjust
waveform of red signal to voltage width (4.0 V) of TP172, which is performed at LCD Gain
adjustment.
CAUTION
Perform section 5.1.8 "LCD Gain Adjustment" before performing this
adjustment.
Step1. Use the Ch2 of oscilloscope, and solder an extended cable to TP173 so that you
can check waveform by the oscilloscope. (Same shape of waveform as figure5-12)
Turn VR177 and adjust until TP173 waveform becomes VG ± 0.2 V, comparing with
Step2.
VG(4.0Vp-p) of TP172 waveform.
T P 1 7 3
T P 1 7 2
T P 1 7 5
T P 1 7 2
T P 1 7 3
T P 1 7 1
T P 1 7 4
V R 1 7 7
V R 1 7 7
V R 1 7 8
Rev. A
C A 2 B o a r d
V R 1 7 1
Figure 5-16. TP173, VR177 and TP173 waveform
PhotoPC600
Chapter5 Adjustment
R G B S i g n a l
V G
T P 1 7 2 W a v e f o r m
R G B S i g n a l
V G +
0 . 2 V
T P 1 7 3 W a v e f o r m
5-14