Q TUNER C.B
3
41CN701
6TP8TP9
(LCH)(GND)(RCH)
8
9
7
TP3(DC)TP4(DC)
L981TP2(CLK)
IC771
31
L771L772
FFE8017
TP1(VT)
TP5(STOP)
2 514
< TUNER SECTION >
1. Clock Frequency Check7. DC Balance / Mono Distortion Adjustment
Settings : Y Test point :TP2 (CLK)Settings : Y Test point :TP3,TP4 (DC balance)
Method : Set to AM 1710kHz and check that the testY Adjustment location : L771
point is 2160kHz ? 45Hz.Y Input level :60dB?V
Method : Set to FM 98.0MHz and adjust L771 so that
2. AM VT Checkthe voltage between TP3 and TP4 becomes
Settings : Y Test point :TP1 (VT)0V ? 0.04V.
Method : Set to AM 1710kHz and check that the testNext, check that the distortion is less than
point is less than 8.5V. Then set to AM1.3%.
530kHz and check that the test point is more
than 0.6V.8. Output Level Check
<AM>
3. AM Tracking AdjustmentSettings : Y Test point :TP8 (Lch), TP9 (Rch)
Settings : Y Test point :TP8 (Lch), TP9 (Rch)Method : Set to AM 1000kHz and check that the test
Y Adjustment location : L981 (1/3)point is 130mV ? 3dB.
Method : Set to AM 1000kHz and adjust L981 (1/3) so
that the test point becomes maximum.<FM>
Settings : Y Test point :TP8 (Lch), TP9 (Rch)
4. AM IF AdjustmentMethod : Set to FM 98.0MHz and check that the test
Settings : Y Test point :TP8 (Lch), TP9 (Rch)point is 520mV ? 3dB.
Y Adjustment location :
L772 ........................... 450kHz9. FM Separation Check
Settings : Y Test point :TP8 (Lch), TP9 (Rch)
5. FM VT CheckY Input level :60dB?V
Settings : Y Test point :TP1 (VT)Method : Set to FM 98.0MHz and check that the test
Method : Set to FM 108.0MHz and check that the testpoint is more than 25dB.
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 : Y Test point :TP8 (Lch), TP9 (Rch)
Method : Set to FM 98.0MHz and check that the test
point is less than 9dB?V.
� 43 �
ACEC
