Electrical Adjustment; Practical Service Figure - Aiwa AV-DV75 Service Manual

ELECTRICAL ADJUSTMENT

3
TUNER C.B
FFE801
L772
4
TP1
L981
TP3
TP2
1/3
4
< TUNER SECTION >
1. Clock Frequency Check
Settings: • Test point: TP2 (CLK IC770 pin30)
Method: Set to AM 1602kHz and check that the test
point becomes 2052kHz±45Hz.
2. AM VT Check
Settings: • Test point: TP1 (VT)
Method: Set to AM 1710kHz and check that the test
point is less than 8.5V.
Then set to AM 530kHz and check that the test
point is more than 0.6V.
3. AM IF Adjustment
Settings: • Test point: TP5, TP6
L772 .............................................. 450kHz
4. AM Tracking Adjustment
Settings: • Test point: TP5, TP6
• Adjustment location: L981 (1/3)
Method: Set to AM 999kHz and adjust L981 so that the
test point becomes maximum.
5. FM VT Check
Settings: • Test point: TP1 (VT)
Method: Set to FM 87.5MHz, 108.0MHz and check that
the test point is more than 0.5V (87.5MHz) and
less than 8.0V (108.0MHz).
6. DC Balance/Mono Distortion Adjustment
Settings: • Test point: TP3, TP4
• Adjustment location: L771
• Input level: 60dB
Method: Set to FM 98.0MHz and adjust L771 so that
the voltage between TP3 and TP4 becomes
0V±0.04V.
Next, check that the distortion is less than
1.3%.
6
TP6
L771
IC771
TP5
TP3
TP4
TP4

PRACTICAL SERVICE FIGURE

< TUNER SECTION >
<FM SECTION>
Signal to noise ratio: More than 62dB
(at 98.0MHz)
Distortion: Less than 2.0%
(Input: 60dB) (at 98.0MHz)
Stereo separation: More than 22dB
(at 98.0MHz)
Intermediate frequency: 10.7MHz
<AM SECTION>
Sensitivity: Less than 60dB (at 600kHz)
(S/N 20dB) Less than 58dB
(at 1000/1400kHz)
Signal to noise ratio: More than 36dB
(Input: 74dB) (at 1000kHz)
Distortion: Less than 1.5%
(at 1000kHz)
Intermediate frequency: 450kHz
37
IC BLOCK DIAGRAM
IC, BU4094BCF
IC, M62431FP
IC, BA3880S
38