Aiwa Z-L720U Service Manual page 27

ADJUSTMENT < TUNER / DECK / FRONT >
< TUNER SECTION >
1. Clock Frequency Check
Settings : • Test point :
Method : Set to AM 1710 kHz and check that the test point is
2160 kHz ± 45 Hz.
2. AM VT Check
Settings : • Test point :
Method : Set to AM 1710 kHz and check that the test point is
less than 8.5 V. Then set to AM 530 kHz and check
that the test point is more than 0.6 V.
3. FM VT Adjustment
Settings : • Test point :
• Adjustment location : L906
Method : Set to FM 108.0 MHz and adjust L906 so that the test
point becomes 7.0 V ± 0.1 V. Then set to FM 87.5
MHz and check that the test point is more that 0.4 V.
4. AM Tracking Adjustment
Settings : • Test point :
• Adjustment location : L951 (1/3)
Method : Set to AM 1000 kHz and adjust L951 (1/3) so that the
test point becomes maximum.
5. FM Tracking Adjustment
Settings : • Test point :
• Adjustment location : L903
Method : Set to FM 87.5 MHz and adjust L903 so that the test
point is less than 9dbµV.
6. AM IF Adjustment
Settings : • Test point :
• Adjustment location :
L802 ........................... 450 kHz
TP2 (CLK)
TP1 (VT)
TP1 (VT)
TP8 (Lch), TP9 (Rch)
TP8 (Lch), TP9 (Rch)
TP8 (Lch), TP9 (Rch)
7. DC Balance / Mono Distortion Adjustment
Settings : • Test point :
• Adjustment location : L801
• Input level :
Method : Set to FM 98.0 MHz and adjust L801 so that the
voltage between TP3 and TP4 is 0 V ± 500 mV.
Next, check that the distortion is less that 1.2%.
8. Output Level Check
<AM>
Settings : • Test point :
• Input level :
Method : Set to AM 1000 kHz and check that the test point is
50 mV ± 3dB.
<FM>
Settings : • Test point :
• Input level :
Method : Set to FM 98.0 MHz and check that the test point is
200 mV ± 3dB.
9. FM Separation Check
Settings : • Test point :
• Input level :
Method : Set to FM 98.0 MHz and check that the test point is
more than 25dB.
– 27 –
TP3, TP4 (DC balance)
TP8(Lch), TP9(Rch)
(Mono Distortion)
60dBµV
TP8 (Lch), TP9 (Rch)
74dBµV
TP8 (Lch), TP9 (Rch)
60dBµV
TP8 (Lch), TP9 (Rch)
60dBµV