Aiwa RC-AAT15, Service Manual

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34
ADJUSTMENT <TUNER>
1. Clock Frequency Check
Settings : • Test point : TP2 (CLK)
Method : Set to MW 1602kHz and check that the test point
is 2052kHz
±
45Hz.
2. MW VT Check
Settings : • Test point : TP1 (VT)
Method : Set to MW 1602kHz and check that the test point
is less than 8.0V. Then set to MW 531kHz and
check that the test point is more than 0.6V.
3. MW Tracking Adjustment
Settings : • Test point : TP8 (Lch), TP9 (Rch)
• Adjustment location : L981 (1/3)
Method : Set to MW 999kHz and adjust L981 (1/3) so that
the test point becomes maximum.
4. LW VT Adjustment
Settings : • Test point : TP1 (VT)
• Adjustment location : L942
Method : Set to LW 144kHz and adjust L942 so that the
test point becomes 1.3V
±
0.05V.
Then set to LW 290kHz and check that the test
point is less than 8.0V.
5. LW Tracking Adjustment
Settings : • Test point : TP8 (Lch), TP9 (Rch)
• Adjustment location :
L941 .................................................... 144kHz
TC942 .................................................. 290kHz
Method : Set up TC942 to center before adjustment.
The level at 144kHz is adjusted to maximum by
L941. Then the level at 290kHz is adjusted to
maximum by TC942.
6. AM IF Adjustment
Settings : • Test point : TP8 (Lch), TP9 (Rch)
• Adjustment location :
L772 .................................................... 450kHz
7. FM VT Check
Settings : • Test point : TP1 (VT)
Method : Set to FM 108.0MHz and check that the test point
is less than 8.0V. Then set to FM 87.5 MHz and
check that the test point is more than 0.5V.
8. FM Tracking Check
Settings : • Test point : TP8 (Lch), TP9 (Rch)
Method : Set to FM 98.0MHz and check that the test point
is less than 13dB
µ
V.
9. DC Balance / Mono Distortion Adjustment
Settings : • Test point : TP3,TP4 (DC balance)
TP8 (Lch), TP9 (Rch) (Distortion)
• Adjustment location : L771
• Input level : 60dB
µ
V
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%.
L771
L981
L772
FFE801
1
IC771
TP1(VT)
TP2(CLK)
TP4(DC) TP3(DC)
1
CN701
(GND)
TP8
(LCH)
TP9
(RCH)
TUNER C.B M
1 2
3
3
5
6 4
6
8
9
9
7
TC942
L941 L942
4
5
9
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