Vco Free Run Frequency Adjustment; Bl Drive Voltage Adjustment; Vcom Ac Adjustment And Vcom Dc Coarse Adjustment - Casio QV-7000SX Service Manual & Parts List

3-4. VCO free run frequency adjustment

Room temperature should be 20 ± 10 ºC
1. Preparation
• AC adaptor or voltage regulator
• Frequency counter
2. Adjustment procedure
(1) Connect CP733 (SYF) and CP700 (GND).
(2) Monitor CP704 (HDB) with frequency counter and adjust VR755 so that frequency becomes
15.734 ± 0.1 KHz.
(3) After completing adjustment, disconnect CP7033 (SYF) and CP700 (GND).
3. Notes
When unable to adjust using AC adaptor, use voltage regulator and supply power to be VCC-1-1
(CP149) = 5.0 ± 0.05 V.

3-5. BL drive voltage adjustment

1. Preparation
• AC adaptor or voltage regulator
• Multimeter
2. Adjustment procedure
Make sure that CP910 (BL-VCC) is within 5.4 ± 0.2V.
3. Notes
When unable to adjust using AC adaptor, use voltage regulator and supply power to be VCC-1-1
(CP149) = 5.0 ± 0.05 V.

3-6. VCOM AC adjustment and VCOM DC coarse adjustment

1. Preparation
• AC adaptor or voltage regulator
• Digital oscilloscope
2. Adjustment procedure
(1) Make sure amplitude of VCOM output (CP176) is 6.6 ± 0.3 V.
(2) Adjust VR320 so that maximum VCOM output (CP716) will be 4.8 ± 0.2 V.
3. Notes
When unable to adjust using AC adaptor, use voltage regulator and supply power to be VCC-1-1
(CP149) = 5.0 ± 0.05 V.
VCC1-1
Power
Supply
QV-7000SX
L-PCB
VCOM
(CP716)
(CP149)
— 15 —
High level
4.8 [V]
0 [V]
–1.8 [V]
Oscilloscope