Rgb Amp, Sub Bright Adjustment - Casio QV-3000EX Service Manual & Parts List

4-3. RGB AMP, Sub bright adjustment

1. Adjustment procedure
• Make sure
(CP344) = 5.0 ± 0.05 [V]
VCC5
(CP391) = 15.0 ± 0.45 [V]
VCC15
(CP390) = 8.0 ± 0.05 [V]
VCC7
(CP220) = 3.3 ± 0.08 [V]
VCC3
2. Preparation
• AC adaptor or voltage regulator
• Frequency counter
3. Adjustment and checking
(1) Turn the power on while pressing DISP and MENU keys simultaneously. (TEST MODE)
(2) Push PREVEIW
(3) Select GRAY SCALE (10STEP) and execute.
(4) Apply VCC5-1 (CP362) on the killer terminal (CP308) via 22k ohm resistor.
(5) Trigger VB waveform (CP322) by FRP (CP305) signal to adjust as noted below.
(6) Adjust RGB-AMP VR (VR302) so that VG waveform (CP322)'s pedestal-pedestal voltage is 4.30
± 0.05 Vp-p.
(7) Adjust SUB R BRIGHT VR (VR305) so that VR waveform (CP320)'s pedestal-pedestal voltage is 4.30
± 0.05 Vp-p.
(8) Adjust SUB B BRIGHT VR (VR304) so that VB waveform (CP324)'s pedestal-pedestal voltage is 4.20
± 0.05 Vp-p.
* Make sure that waveforms are not distorted.
* Proceed to CONTRAST, BRIGHT adjustments.
Power
Supply
PREVEIW MENU keys in order rapidly. (TEST MODE 1)
QV-3000EX
D-PCB
VCC15
(CP391)
VCC5
(CP344)
VCC7
(CP390)
VCC3
(CP220)
— 25 —
VCC5-1
22KΩ
Killer terminal
(CP308)
VR(CP320)
Digital oscilloscope
VG(CP322)
Figure 3-1
VB(CP324)
4.30 ± 0.05 or 4.20 ± 0.05V
(pedestal-pedestal)
3-1