Casio EV-660C, Руководство по обслуживанию

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3. Free running frequency adjustment
•
Conditions
(1) Signal
No signal (PAL standard signal should be applied only at synchronous check)
(2) Signal level
Input electric field only at synchronous check: 70
±
3 dB
µ
(terminated with 75
Ω
resistance),
P/S = 10 dB
(3) Other conditions
CCIR IF input only at synchronous check (input electric field with 75
Ω
termination).
Connect SYF terminal (CP725) and GND.
Power supply: Vcc1-1 = 5.00
±
0.05 [V]
Room temperature: 20
±
10 [
°
C]
•
Adjustment
Monitoring HDB (CP705) with a frequency counter, adjust VR710 so that the frequency is 15.625
±
0.1 [kHz].
•
Caution
(1) Disconnect the wire between SYF terminal. Applying IF signal make sure that synchronization is normal
on the display.
•
Block diagram
L-PCB
SYF
GND
HDB
Frequency
Counter
VCC1-1
IF signal
Signal
generator
Stabilizer
4. VCOM AC and VCOM DC coarse adjustment
• Conditions
(1) Signals
Broadcasting system: B/G
Color system: PAL color bar
(2) Signal level
Input electric field: 70
±
3dB
µ
(terminated with 75
Ω
resistance), P/S = 10 dB
(3) Others
CCIR IF input (input electric field should be terminated with 75
Ω
resistance)
Use VIDEO signal equivalent to TG7.
Power supply should be Vcc1-1 = 5.00
±
0.05V.
• Adjustment
(1) Confirm that the amplitude of VCOM output (CP750) is 6.0
±
0.5 [V].
(2) Adjust VR730 so that Low level voltage of VCOM output (CP750) is 2.4
±
0.2 [V].
•
Block diagram
GND
2.4 V
6.0 V
VCC1-1
IF signal
Signal
generator
Stabilizer
L-PCB
CP750
Oscilloscope