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IC801
IC991
L955
L907
L904
L954
L903
L802
CN991
CN991
TP9 1pin
TP8 2pin
GND 12pin
TP2
IC801
R815
R962
TP3
TP4
TP1 (24pin)
PART SIDE
PATTERN SIDE
1
1
5
5
2 3
2 3
4
2
6 7
6 7
6
7
5
FREQUENCY COUNTER
DIGITAL MULTIMETER
DIGITAL MULTIMETER
DIGITAL MULTIMETER
VT
GND
VT
GND
TP
GND
TP
Hz
V
V
V
GND
ELECTRICAL ADJUSTMENT -1/6
<TUNER SECTION>
1. CLOCK CHECK
Requirements
Measuring equipment: Frequency counter
Test point: TP1 (CLOCK), GND
1) Adjust the reception frequency of the main unit to 1,710 kHz.
2) Check that the test point frequency is 2160 ± 0.045 kHz.
2. VT ADJUSTMENT (FM)
Requirement
Measuring equipment: Digital multi-meter
Test point: TP4 (R962), GND
Adjustment point: L907
1) Adjust the reception frequency of the main unit to 108.0 MHz.
2) Adjust L907 until the test point voltage (VT) is 7.0 V ± 0.1 V.
3) Adjust the reception frequency of the main unit to 87.5 MHz.
4) Check that the test point (VT) voltage is about 1.5 V.
3. VT CHECK (AM)
Requirement
Measuring equipment: Digital multi-meter
Test point: TP4 (R962), GND
1) Adjust the reception frequency of the main unit to 530 kHz.
2) Check that the test point (VT) voltage is about 0.5 V.
3) Adjust the reception frequency of the main unit to 1710 kHz.
4) Check that the test point (VT) voltage is below 9.0 V.
4. DC BALANCE CHECK
Requirement
Measuring equipment: Digital multi-meter
Test point: TP2, 3
1) Adjust the reception frequency of the main unit to 98.0 MHz.
2) Check that the test point voltage difference between TP2 and TP3 is 0 mV ± 500 mV.