ELECTRICAL ADJUSTMENT
TUNER C.B
FFE801
3
6
IC BLOCK DIAGRAM IC, BU4094BCF
TP6
4
L772 TP1 L981
L771
TP3 TP2 1/3 TP4
IC771 TP3 TP4 TP5
4
< TUNER SECTION >
1. Clock Frequency Check Settings: � Test point: TP2 (CLK IC770 pin30) Method: Set to AM 1602kHz and check that the test point becomes 2052kHz±45Hz. 2. AM VT Check Settings: � Test point: TP1 (VT) 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 IF Adjustment Settings: � Test point: TP5, TP6 L772 .............................................. 450kHz 4. AM Tracking Adjustment Settings: � Test point: TP5, TP6 � Adjustment location: L981 (1/3) Method: Set to AM 999kHz and adjust L981 so that the test point becomes maximum. 5. 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). 6. DC Balance/Mono Distortion Adjustment Settings: � Test point: TP3, TP4 � Adjustment location: L771 � Input level: 60dB 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%.
IC, M62431FP
PRACTICAL SERVICE FIGURE
< TUNER SECTION >
<FM SECTION> Signal to noise ratio: Distortion: (Input: 60dB) Stereo separation: Intermediate frequency: <AM SECTION> Sensitivity: (S/N 20dB) Signal to noise ratio: (Input: 74dB) Distortion: Intermediate frequency: More than 62dB (at 98.0MHz) Less than 2.0% (at 98.0MHz) More than 22dB (at 98.0MHz) 10.7MHz
Less than 60dB (at 600kHz) Less than 58dB (at 1000/1400kHz) More than 36dB (at 1000kHz) Less than 1.5% (at 1000kHz) 450kHz
IC, BA3880S
37
38
