Vco Free Run Frequency Adjustment; Method To Confirm S Character (Focus Error) - Pioneer CJ-V55 Service Manual

CJ-V55
Step
No.
Oscilloscope Setting
_ j -
Test Points
Adjusting
Points
Check items/
Adjustment
specifications
Adjustment procedure
10 VCO FREE RUN FREQUENCY ADJUSTMENT
TP2
Pin 8
(PLCK)
VR8
(VCO. AD J)
4.275 ± 0.01MHz
• Set to Service mode.
• Short-circuit between pin 25 and pin 26 of IC1 in the
DEGT assembly with © screwdriver, etc. (Fig. 7-6)
• Connect frequency counter, which is measurable over
10MHz, to pin 8 of TP2 (PLCK).
• Adjust with VR8 VCO. ADJ (VCO adjustment) volume
so that the value of frequency counter becomes 4.275
± 0.01MHz.
11 METHOD TO CONFIRM S CHARACTER (FOCUS ERROR) |
TP1
Pin 6
(PCS. ERR)
• Set to Service mode.
• Short-circuit between pin 5 FCS.IN (Focus in) of
TP1 and GND.
• Press 1-MULTI-SPEED+1 kev +m and observe the
waveform of pin 6 FCS. ERR (Focus error) of TP1
at that time with an oscilloscope.
MM
■Pi—
MM
Photo. 7-16 Focus error
101