Color Adjustment; Vcom Dc Adjustment - Casio QV-780 Service Manual & Parts List

3-7.Color adjustment

• Perform this procedure together with BCC adjustment.
• Show color bar in test mode.
• Power supply voltage VCL 0 (CP101) = 5.0 ± 0.05 V(For normal check, AC adaptor can be used,
however, when the camera is faulty, apply the above mentioned voltage.)
• Adjust VR300 so that the first 1 the second 2 pulse of VB waveform (CP324) becomes 4.1 ± 0.1 V.
(1) Perform this procedure after contrast adjustment.
(2) Set the pedestal voltage of VB to 5.0 ± 0.1 Vp-p by adjusting BRIGHT VR (VR302).
(3) Use FRP (CP711) for trigger.
(4) If waveform changes by adjusting BCC perform step (2).
(5) Make sure 3 and 4 have almost the same value.
Power
Supply

3-8.VCOM DC adjustment

• Perform this adjustment when you replace the display module.
• No signal input
• BRIGHT VR: Maximum
• Apply 6.0 ± 0.1 [V] (DC in). (For normal check, AC adaptor can be used, however, when the camera
is faulty, apply the above mentioned voltage.)
(1) Adjustment VR350 if the display is flikered, dimmed or discolored with watching the LCD screen.
(2) If the adjustment cannot be done well, passing photosensor amp output signal through 60 Hz
band-pass filter, adjust VR350 to minimize the ripple of 60 Hz signal as shown below.
Photo diode
S1153
QV-780
Power supply
L-PCB
VB terminal
(CP324)
Photosensor amp.
C2719
— 15 —
4.1 ± 0.1 [V]
1
2
B.P.F.
Oscilloscope
Adjust VR350
to minimize the
ripple.
2
4
3
1
3
4
Oscilloscope