(No.MB330)1-21
4.2
Tuner section
Item
Measuring condition
Check and adjustment procedure
Standard value Adjusting point
AM IF
adjustment
T101
T102
T103
Signal input : T002
Signal output : T007
1.T026 and T006 connected with a 3.3k ohm
resistor.
2.Set the intermediate frequency sweep
generator to AM 450 kHz.
3.T021 and GND connected with a 220 ohm
resistor and a 104 capacitor in serials.
Adjust the T102 for maximum and center
output.
4.T022 and GND connected with a 220 ohm
resistor and a 104 capacitor in serials.
Adjust the T101 for maximum and center
output.
5.T002 input 2mV 450kHz signal without MOD.
Adjust the T103 until the voltage between
T009 and T010 is 0mV 3mV.
AM tracking
adjustment
T104
T106
TC102
Signal input : Loop
antenna
Signal output : phone
(with 32 ohm load)
1.Set the TUNER at 1629 kHz adjust T104
until the test pin of T008 voltage at 7.0V
0.1V.
2.Set the TUNER at 522 kHz, check the pin of
T008 voltage at 1.1V 0.5V.
3.Set the TUNER and S/G at 603 kHz, adjust
T106 for maximum output.
4.Set the TUNER and S/G at 1404 kHz, adjust
TC102 for maximum output.
5.Repeat the above step 3 and 4.
FM IF
adjustment
T105
L102
Signal input : T004
Signal output : T007
1.Set the TUNER at 108 MHz, adjust L102
until the test pin of T008 voltage at 8.0 V
0.1V.
2.Set the TUNER at 87.5 MHz, check the pin
of T008 voltage at 1.6 V 0.5V.
3.Short T011 and GND, adjust the T105 until
the voltage between T009 and T010 is 0 mV
0.5V.
FM tracking
adjustment
L101
TC101
Signal input : ANT IN
Signal output : phone
(with 32 ohm load)
1.Set the TUNER and S/G at 90 MH, adjust
L101 for maximum output.
2.Set the TUNER and S/G at106 MHz, adjust
TC101 for maximum output.
3.Repeat the above step 1 and 2.
