Electrical Adjustment - Aiwa XR-M88 Service Manual

ELECTRICAL ADJUSTMENT

CD C.B
< CD SECTION >
Note: • Connect a probe (10: 1) of the oscilloscope test point
for adjustment.
• Connect ground (-) terminal of oscilloscope probe to
TP3 (VREF) for all adjustment.
1. Focus Bias Adjustment
Make the focus bias adjustment when replacing and repairing
the optical block.
TP1 (RF)
TP2 (VREF)
1) Connect an oscilloscope to test points TP1 (RF) and TP2
(VREF).
2) Turn on the power switch.
3) Insert test disc TCD-782 (YEDS-18) and play back the
second program.
4) Adjust SFR103 so that RF signal of the test point TP1 (RF) is
MAX and CLEARREST.
EYE PATTERN
must be CLEAR and MAX.
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TP1
(RF)
Oscilloscope
(DC range)
+
–
MAX
1.8±0.1 Vp-p
0V
VOLT/DIV: 0.5V
TIME/DIV: 0.5µS
54
1
TP2
(VREF)
SFR130
IC1
CN2
TP3
(TE)
R2
2. Tracking Balance Check
TP3 (TE)
TP2 (VREF)
1) Connect an oscilloscope to test points TP3 (TE) and TP2
(VREF).
2) Start up the CD test mode.
3) Insert the test disc TCD-782 (YEDS-18) and enter the
traverse mode of the CD test mode.
4) Confirm that the traverse waveform on an oscilloscope is
vertically symmetrical as shown in the figure below.
5) After confirming the waveform, release the CD test mode.
VREF
A=B
3. Laser Current Check
The current of the laser signal can be checked with the
voltages on both sides of R2 (voltage across 10Ω).
The difference for the specified value shown on the label
must be within ± 6.0mA.
KSM620-AAA
15165
SG442
Laser current Iop =
Oscilloscope
(DC range)
+
–
A
B
VOLT/DIV: 20mV
TIME/DIV: 1mS
44.2mA
Voltage across R2
10Ω