Aiwa AV-DV75 Service Manual page 24

ELECTRICAL ADJUSTMENT
TUNER C.B
FFE801
4
TP1
TC942
L981
L941
7
4
< TUNER SECTION >
1. Clock Frequency Check
Settings: • Test point: TP2 (CLK IC771 pin30)
Method: Set to AM 1602kHz and check that the test
point becomes 2052kHz±45Hz.
2. MW VT Check
Settings: • Test point: TP1 (VT)
Method: Set to AM 1602kHz and check that the test
point is less than 8.0V.
Then set to AM 531kHz and check that the test
point is more than 0.6V.
3. MW IF Adjustment
Settings: • Test point: TP5, TP6
L772 .............................................. 450kHz
4. MW 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. LW VT Adjustment
Settings: • Test point: TP1 (VT)
• Adjustment location: L942
Method: Set to LW 144kHz and adjust L942 so that the
test point is 1.3V±0.05V.
Then set to 290kHz and check that the test
point is less than 8.0V.
7. LW Tracking Adjustment
Settings: • Test point: TP5, TP6
• Adjustment location: L941, TC942
Method: Set to LW 144kHz and adjust L941 so that the
test point becomes maximum.
Then set to LW 290kHz and adjust TC942
so that the test point becomes maximum.
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3
TP5
L772
L771
8
IC771
L942
TP2 TP6
TP3
TP4
6
8. 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%.
PRACTICAL SERVICE FIGURE
< TUNER SECTION >
< FM SECTION >
Sensitivity: Less than 14dBµV
(at 87.5MHz)
Less than 13dBµV
(at 98.0/108.0MHz)
Signal to noise ratio: More than 68dB
(at 98.0MHz)
Distortion: Less than 1.2%
(Input: 60dB) (at 98.0MHz)
Stereo separation: More than 12dB
(at 98.0MHz)
Intermediate frequency: 10.7MHz
< MW 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
< LW SECTION >
Sensitivity: Less than 70dBµV
(S/N 20dB) (at 144kHz)
Less than 68dBµV
(at 198kHz)
Less than 66dBµV
(at 290kHz)
37
FL (BJ691GK) GRID ASSIGNMENT/ANODE CONNECTION
GRID ASSIGNMENT
ANODE CONNECTION
38