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4
7
8
TP7
(STOP)
L771
L772
1
770
TP5
L981
(DC)
TP3
(CLK)
TP6
TP4(VT)
(DC)
FFE801
4. AM IF Adjustment
Settings : • Test point :
TP8(Lch), TP9(Rch)
he test
L772 ........................... 450kHz
5. FM VT Check
Settings : • Test point :
TP4(VT)
Method :
Set to FM 87.5MHz and check that the test
he test
point is more than 0.5V.
Then set to FM 108.0MHz and check that the
hat the
test point is less than 8.5V.
6. FM Tracking Check
Settings : • Test point :
TP8(Lch), TP9(Rch)
P9(Rch)
Method :
Set to FM 98.0MHz and check that the test
point is less than 9dB.
1/3) so
m.
53
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7. DC Balance / Mono Distortion Adjustment
Settings : • Test point :
• Adjustment location : L771
• Input level :
Method :
Set to FM 98.0 MHz and adjust L771 so that
the voltage between TP5 and TP6 becomes
3
0V ± 0.04V.
Next, check that the distortion is less than
1.3%.
2
5
8. Auto Stop Level Check
<AM>
Settings : • Test point :
• Input level :
Method :
Set to AM 999kHz and check that the auto
stop is at input level of 50dB +10 /–15dB.
<FM>
Settings : • Test point :
• Input level :
Method :
Set to FM 98.0MHz and check that the auto
stop is at input level of 25dB ± 10dB.
9. Output Level Check
<AM>
Settings : • Test point :
• Input level :
Method :
Set to AM 999kHz and check that the test
point is 30mV ± 3dB.
<FM>
Settings : • Test point :
• Input level :
Method :
Set to FM 98.0MHz and check that the test
point is 120mV ± 3dB.
10. FM Separation Check
Settings : • Test point :
• Input level :
Method :
Set to FM 98.0MHz and check that the test
point is more than 25dB.
PRACTICAL SERVICE FIGURE
<TUNER SECTION>
TP5, TP6
(DC balance)
<FM SECTION>
TP8, TP9
IHF Sensitivity :
Less than 10dB
(Distortion)
(THD 3%)
[at 87.5MHz]
Less than 9dB
54dB
[at 98.0 / 108.0MHz]
S/N 50dB Quieting sensitivity :
Less than 36dB
[at 87.5 / 98.0 / 108.0MHz]
Signal to noise ratio :
More than 68dB (MONO)
(Input 54dB)
More than 66dB (STEREO)
[at 98.0MHz]
Distortion :
Less than 1.2% (MONO)
(Input 54dB)
Less than 2.0% (STEREO)
TP7(STOP)
[at 98.0MHz]
50dB
Auto stop level :
25dB ± 10dB
[at 98.0MHz]
Stereo separation :
More than 30dB
[at 98.0MHz]
Intermediate frequency : 10.7MHz
TP7(STOP)
25dB
<AM SECTION>
Sensitivity :
Less than 62dB
[at 603kHz]
Less than 58dB
[at 999 / 1404kHz]
Signal to noise ratio :
More than 36dB
TP8(Lch), TP9(Rch)
(Input 74dB)
[at 999kHz]
74dB
Distortion :
Less than 1.5%
[at 999kHz]
Auto stop level :
50dB + 10/– 15dB
[at 999kHz]
Intermediate frequency : 450kHz
TP8(Lch), TP9(Rch)
54dB
TP8(Lch), TP9(Rch)
54dB
54
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