Aiwa NSX-DP25 Service Manual page 29

ADJUSTMENT <TUNER / DECK / FRONT>
< 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.
6. LW Tracking Adjustment
Settings : • Test point : TP8 (Lch), TP9 (Rch)
• Adjustment location :
L941 ..........................................................144kHz
TC942 ........................................................290kHz
Method : Set up TC942 to center before adjustment.
Adjust L941 so that the level at 144kHz becomes
maximum. Then adjust TC942 so that the level at
290kHz becomes maximum.
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
than 13dBµV.
8. AM IF Adjustment
Settings : • Test point : TP8(Lch), TP9(Rch)
• Adjustment location :
L802 ................................................ 450kHz
9. DC Balance / Mono Distortion Adjustment
Settings : • Test point : TP3, TP4 (DC Balance)
TP8(Lch), TP9(Rch) (Distortion)
• Adjustment location : L801
• Input level : 60dBµV
Method : Set to FM 98.0MHz and adjust L801 so that the voltage
between TP3 and TP4 becomes 0V ± 0.3V.
Next, check that the distortion is less than 1.3%.
< DECK SECTION >
10. Tape Speed Adjustment (DECK 2)
Settings : • Test tape : TTA–100
• Test point : TP8(Lch), TP9(Rch)
• Adjustment location : SFR1
Method : Play back the test tape and adjust SFR1 so that the
frequency counter reads 3000Hz ± 5Hz (FWD) and
FWD SPEED ± 45Hz (REV).
11. Head Azimuth Adjustment (DECK 1, DECK 2)
Settings : • Test tape : TTA–330
• Test point : TP8(Lch), TP9(Rch)
• Adjustment location : Azimuth adjustment screw
Method : Play back (FWD) the 8kHz signal of the test tape and
adjust screw so that the output becomes maximum.
Next, perform on REV PLAY mode.
12. PB Frequency Response Check (DECK 1, DECK 2)
Settings : • Test tape : TTA–330
• Test point :TP8(Lch), TP9(Rch)
Method : Play back the 315Hz and 8kHz signals of the test tape
and check that the output ratio of the 8kHz signal with
respect to that of the 315Hz signal is within 5dB.
13. PB Sensitivity Check (DECK 1, DECK 2)
Settings : • Test tape : TTA–200
• Test point : TP8(Lch), TP9(Rch)
Method : Play back the test tape and check that the output level of
the test point is 110mV ± 3dB.
14. REC/PB Frequency Response Adjustment (DECK 2)
Settings : • Test tape : TTA–602
• Test point : TP8(Lch), TP9(Rch)
• Input signal : 1kHz / 8kHz (LINE IN)
• Adjustment location : SFR351 (Lch), SFR352 (Rch)
Method : Apply a 1kHz signal and REC mode. Then adjust OSC
attenuator so that the output level at the TP8, TP9
becomes -20VU (-26dBV). Record and play back the
1kHz and 8kHz signals and adjust SFRs so that the
output of the 8kHz signals becomes 0dB ± 0.5dB with
respect to that of the 1kHz signal.
15. REC/PB Sensitivity Check (DECK 2)
Settings : • Test tape : TTA–602
• Test point : TP8(Lch), TP9(Rch)
• Input signal : 1kHz (LINE IN)
Method : Apply a 1kHz signal and REC mode. Then adjust OSC
attenuator so that the output level at TP8, TP9 becomes
0VU (-6dBV). Record and play back the 1kHz signals
and check that the output is -2dB ± 3.5dB.
< FRONT SECTION >
16. µ-con OSC Adjustment
Settings : • Test point : TP11,(KEY-SCAN), GND
• Adjustment location : L951
Method : Connect a frequency counter across TP11 and GND via
a CR network filter. Then adjust L951 so that the test
point becomes 184.94Hz ± 0.18Hz.
< CR NETWORK FILTER >
TP11 10µF 10µF
(KEY-
SCAN)
(GND)
– 29 –
1kΩ 1SS133
1kΩ 0.1µF 47kΩ
TO
FREQ
COUNTER