D-Pcb Assy; Vco Free Run Frequency Adjustment; Vcom Ac Adjustment And Vcom Dc Coarse Adjustment - Casio QV-3000EX Service Manual & Parts List

4. D-PCB Assy

4-1. VCO free run frequency 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
• Room temperature should be 20 ± 10 °C
2. Preparation
• AC adaptor or voltage regulator
• Frequency counter
3. Adjustment and checking
(1) Connect SYF (CP355) and GND (CP350).
(2) Monitor HDB (CP704) with frequency counter and adjust VR320 so that frequency becomes 15.734
± 0.1 KHz.
(3) After completing adjustment, disconnect SYF (CP7033) and GND (CP700).

4-2. VCOM AC adjustment and VCOM DC coarse 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 procedure
(1) Make sure amplitude of VCOM output (CP364) is 6.6 ± 0.3 V.
(2) Adjust VR321 so that maximum VCOM output (CP364) will be 4.8 ± 0.2 V.
4. Note
When unable to adjust using AC adaptor, use voltage regulator and supply power to be VCC1-1 (CP105)
= 5.0 ± 0.05 V.
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