Panasonic Technics ST-CH7L - Page 15

ST-CH7L
m@ MEASUREMENTS AND ADJUSTMENTS
FM ADJUSTMENT
Control positions and equipment used
@FM signal generator (FM-SG)
Stereo modulator
eDistortion analyser
DC electronic voltmeter (EVM)
Frequency counter
Choke coil (100 UH)
Resistor (100 kQ)
Note: For L321, L322, L324, Z321, 2251 (AM-ANT/OSC) and Z202 (AM-IFT), they are supplied as adjusted parts. So, do not turn the cores of
the parts.
It is not necessary to adjust the AM circuit.
FM STEREO DISTORTION ADJUSTMENT
1.Test equipment connection is shown in figure.
2. Set the unit to “FM” mode.
3. Set the radio frequency display and signal generator to
100.10 MHz.
4. Adjust L1 so that the distortion factor of L-CH is minimized.
§. Make sure that the distortion factors of L-CH and R-CH are
nearly the same with each other to minimum.
FM SIGNAL GENERATOR CONDITION
Modulation Stereo “L’’ mode or “R”
mode 45%, Pilot 10%
Modulation frequency
Output level
ajo
FM ANT — Output Distortion analyser
9
Notes: ud
1. The adjusting screwdriver used should be made of resin.
2. L1 should be rotated no more 1/4 turn (90 deg.) on either side.
Stereo modulator
Output mode... L or R
e ADJUSTMENT POINTS
Addition
----, i
1 FM '
| Stereo |
| distortion |
i ;
LINE OUT LINE OUT
(Lech) (Reh)
FM mono
distortion
FM offset
PLL clock Frequency
FM MPX VCO
(ISkHz}