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< TUNER SECTION >
1. Clock Frequency Check
Settings : • Test point :
Method :
Set to AM 1710kHz and check that the test
point is 2160kHz ± 45Hz.
2. AM VT Check
Settings : • Test point :
Method :
Set to AM 1710kHz and check that the test
point is less than 8.5V. Then set to AM
530kHz and check that the test point is more
than 0.6V.
3. AM Tracking Adjustment
Settings : • Test point :
• Adjustment location : L981 (1/3)
Method :
Set to AM 1000kHz and adjust L981 (1/3) so
that the test point becomes maximum.
4. AM IF Adjustment
Settings : • Test point :
• Adjustment location :
L772 ........................... 450kHz
5. FM VT Check
Settings : • Test point :
Method :
Set to FM 108.0MHz and check that the test
point is less than 8.0V. Then set to FM
87.5MHz and check that the test point is more
than 0.5V.
6. FM Tracking Check
Settings : • Test point :
Method :
Set to FM 98.0MHz and check that the test
point is less than 9dBµV.
Q
TUNER C.B
3
4
1
TP8
6
(LCH)
(GND)
8
9
L981
3
FFE801
TP2 (CLK)
TP1 (VT)
TP8 (Lch), TP9 (Rch)
TP8 (Lch), TP9 (Rch)
TP1 (VT)
TP8 (Lch), TP9 (Rch)
CN701
TP9
(RCH)
TP3(DC)
TP2(CLK)
IC771
1
L772
TP1(VT)
2
5
1
4
7. DC Balance / Mono Distortion Adjustment
Settings : • Test point :
• Adjustment location : L771
• Input level :
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%.
8. Output Level Check
<AM>
Settings : • Test point :
Method :
Set to AM 1000kHz and check that the test
point is 130mV ± 3dB.
<FM>
Settings : • Test point :
Method :
Set to FM 98.0MHz and check that the test
point is 520mV ± 3dB.
9. FM Separation Check
Settings : • Test point :
• Input level :
Method :
Set to FM 98.0MHz and check that the test
point is more than 25dB.
– 43 –
7
TP4(DC)
L771
7
TP5(STOP)
TP3,TP4 (DC balance)
60dBµV
TP8 (Lch), TP9 (Rch)
TP8 (Lch), TP9 (Rch)
TP8 (Lch), TP9 (Rch)
60dBµV
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