Epson PhotoPC600, Руководство по обслуживанию, Страница: 104 / 116

PhotoPC600
Chapter5 Adjustment
Rev. A 5-11
5.1.7 LCD RGB Offset Adjustment
RGB signals are controlled to be reversed every 1H and converted to alternating component in
order not to let LCD elements to have DC component. RGB Offset adjusts the difference between
RGB and DC common electrode voltage(COM). Since the brightness of LCD elements is
controlled by this electric potential difference between RGB and COM, it is necessary to perform
this adjustment and fix the value of brightness for images on the LCD when replacing CA2 board
or LCD monitor.
CAUTION
Perform section 5.1.8 “LCD Gain Adjustment” after this adjustment.
Step1. Select DscCal52 and display the screen for adjustment program.(Refer to figure5-3)
Step2. Click on an arrow located next to RGB Offset window. (Refer to the figure below)
D s c
C a l .
D s c C a l f o r S R 5 2 V e r . 0 . 8 0 B e t a
U p l o a d
F i r m w a r e
I m a g e
O P F
U p l o a d
E r a s e
F i r m w a r e V e r s i o n : v 5 2 - 7 1 b
B r i g h t n e s s
I n i t i a l i z e
A W B
F o c u s
L C D
R G B O f f s e t
H A F C
C o n t r a s t
G a i n
T e s t
C a l i b r a t i o n
0
0
0
0
0
O f f
R G B O f f s e t A d j u s t m e n t S w i t c h
Figure 5-11. Location of RGB Offset switch
Step3. Remove the chute for optional flash card on the CA2 board, releasing 4 hooks.
Step4. Solder an extended cable to TP172, which is located under the removed chute at
Step3, in order to check the waveform by oscilloscope. (The waveform below
should be seen.)
Step5. Adjust and find an appropriate value so that distance between up peaking and
bottom peaking becomes 7.8V
±
0.3V.
RGB Signal
7.8Vp-p
+ 0.3V
TP175
TP172
TP173
TP171
TP174
TP172
-
Figure 5-12. Location of TP172 and its waveform