Sharp SC-7700CDH - Adjustment; CD Section Preparation; VCO Free-Run Frequency Adjustment; Tracking Error Balance Adjustment

SC- 7700CDH
©
:
ADJUSTMENT
As for adjusting method refer to the relevant explanation in
Service Manual “ADJUSTMENT PROCEDURES OF AUDIO
PRODUCTS”.
CD SECTION
1. Preparation for Adjustment
When adjusting, be sure to refer to Service Manual
"ADJUSTMENT PROCEDURES OF AUDIO PRODUCTS’.
- Test mode of control microcomputer
Depressing the REPEAT button and CALL button, turn on the
power switch.
2.VCO Free-Run Frequency
3. Servo Unit
The procedure of adjustment differs from that stated in
Service Manual “ADJUSTMENT PROCEDURES OF AUDIO
PRODUCTS’.
Follow the procedure stated below.
- Focus Offset
- Tracking Offset
Adjusting
Specified
value
Instrument
Connection
.
Point
Pin
4
and
pin
1
(GND)
++
- Focus Gain
fe ete Adjusting method Instrument Connection
Set the same Both ends of R72
VRi waveform for CH1 (CH1, CH2) and pin 25
and CH2. of |C2
*1: Apply sine wave (Oscillation Frequency 1.0 kHz 1.0.Vrms)
as shown in Figure 20-1.
- Tracking Gain
Set the same Both ends of R120
waveform for CH1 (CH1, CH2) and pin 25
and CH2., of IC2
*2: Apply sine wave (Oscillation Frequency 1.0 kHz 1.0 Vrms}
as shown in Figure 20-2.
- Tracking Error Balance
Pin 2 and pin 25
cea
*3: Short-circuit the pin 4 of IC8 to the ground.
Adjust so as to obtain symmetric waveform (Fig. 19-1)
when DC is OV.
- Check HF output
Pin 36 and pin 25
{GND) of IC2
Make sure that waveform is as shown in Figure 19-2,
More than
1.2 Vp-p
Figure 19—1
6.8 9 A .SpsS
Oke 736 .FkHz
152.0
Vp-p
Figure 19-2
MAIN PWB-E
Figure 19—3 ADJUSTMENT POINTS