Panasonic SC-AK48, Service Manual

Page: 35 / 104

13.1. Tuner Section
13.1.1. Measuring Instruments and
Special Tools
•
AM signal generator (AM-SG)
•
EVM-AC (AC Electronic voltmeter)
•
EVM-DC (DC Electronic voltmeter)
•
Osciloscope
•
Choke coil (100µH)
•
AM loop antenna
Note:
•
Trimmer will be instability that once you tighten, please
adjust with tighten slowly from loosened condition.
•
Adjust OSC coil and IFT with nonmetal driver.
13.1.2. AM IF Adjustment
1. Connect the instrument as shown in Fig.1.
2. Set the unit to AM mode.
3. Apply signal sa shown in Fig.1 from AM-SG.
4. Adjust Z102 so that the output frequency is maximized in
Fig.2.
Fig.1
Fig.2
13.1.3. AM RF Adjustment
1. Connect the instrument as shown in Fig.3.
2. Set the unit to AM mode.
3. Set AM-SG to 522kHz.
4. Receive 522kHz in the unit.
5. Adjust Z101 (OSC) so that the EVM-AC is maximized.
6. Set AM-SG to 603kHz.
7. Receive 603kHz in the unit.
8. Adjust Z101 (ANT) so that the EVM-AC is maximized.
9. Set AM-SG to 522kHz.
10. Receive 522kHz in the unit.
11. Adjust Z101 (OSC) so that the EVM-DC value is within
0.5±1.4V.
Fig.3
13 Measurement and Adjustments
13.1.4. Adjustment point
35
SA-AK48