Aiwa NSX-SZ20 Service Manual page 24

ADJUSTMENT <TUNER / DECK / MICON>
A MAIN C.B
15
14
< TUNER SECTION >
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, 531kHz and check that the test
point is less than 8.0V (1602kHz) and more than
0.6V (531kHz).
3. 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.
4. 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).
5. MW Tracking Adjustment
Settings : • Test point : TP8(Lch), TP9(Rch)
• Adjustment location :
L951(1/3) ...................................... 1000kHz
Method : Set to MW 1000kHz and adjust L951(1/3) to MAX.
14 13 12 11 10
9 8 7
SFR 451
SFR 452
TP8 (LCH)
GND
IC301
TP9 (RCH)
1
6 5 1 9
L801
L802
IC801
24
TP2
(CLK)
6. LW Tracking Adjustment
Settings : • Test point : TP8 (Lch), TP9 (Rch)
Method : Set up TC942 to center before adjustment.
7. FM Tracking Check
Settings : • Test point : TP8(Lch), TP9(Rch)
Method : Set to FM 98.0MHz and check that the test point is less
8. AM IF Adjustment
Settings : • Test point : TP8(Lch), TP9(Rch)
9. DC Balance / Mono Distortion Adjustment
Settings : • Test point : TP3, TP4 (DC Balance)
Method : Set to FM 98.0MHz and adjust L801 so that the voltage
– 24 –
8 9 6
3
TC942
L942
1
TP4(DC BAL)
L951
TP3(DC BAL)
(3/3) (1/3)
TP1(VT)
FFE801
• Adjustment location :
L941 ..........................................................144kHz
TC942 ........................................................290kHz
Adjust L941 so that the level at 144kHz becomes
maximum. Then adjust TC942 so that the level at
290kHz becomes maximum.
than 13dBµV.
• Adjustment location :
L802 ................................................ 450kHz
TP8(Lch), TP9(Rch) (Distortion)
• Adjustment location : L801
• Input level : 60dBµV
between TP3 and TP4 becomes 0V ± 0.04V.
Next, check that the distortion is less than 1.3%.
6
L941
5
2
3
4