Panasonic TH-42PA20U/P, Service Manual

Page: 246 / 319

11 Adjustment
11.1. MTS Adjustment
11.1.1. Input level Adjustment
Instrument name Connection Remarks
1. Filter jig
2. 2 RF signal generator
3. RMS voltage meter
4. Measurement computer
TP215 (L out)
RF ANT. INPUT
Filter jig
SCL2, SDA2, FA2
Procedure Remarks
1. Apply following RF signal at Antenna input.
VIDEO : Flat field , 30% modulation
AUDIO : 300Hz ,100% modulation ,monaural
(70dB ± 5dB, 75
9
OPEN, P/S 10dB)
Note:
Make sure 75us PRE-EMPHASIS is off.
2. Adjust "MTSIN" data (Input level) until the RMS voltage meter indicates 106mVrms ±
6mVrms.
11.1.2. STERO Sep. Adjustment
Instrument name Connection Remarks
1. RF signal generator
2. Oscilloscope
3. Measurement computer
RF ANT. INPUT
TP216-GND
SCL2, SDA2, FA2
Procedure Remarks
1. Select STEREO mode in the AUDIO Menu.
2. Apply following RF signal at Antenna input.
VIDEO : Flat field , 30% modulation
AUDIO : 300Hz ,30% modulation ,STEREO (LEFT only)
(70dB ± 5dB ,75
9
OPEN ,P/S 10dB)
Note:
After setting 30% modulation with P.L. SW and N.R. SW off, turn P.L. SW and N.R.
SW on.
3. Adjust "SEPAL" data (Low-level separation) until the amplitude.
4. Apply following RF signal at Antenna input.
VIDEO : Flat field , 30% modulation
AUDIO : 3kHz ,30% modulation ,STEREO (LEFT only)
(70dB ± 5dB, 75
9
OPEN, P/S 10dB)
Note:
After setting 30% modulation with P.L. SW and N.R. SW off, turn P.L. SW and N.R.
SW on.
5. Adjust "SEPAH" data (High-level separation) until the amplitude of the waveform on the
oscilloscope is minimum.
6. Repeat steps 2. to 5. until Low-level separation and High-level separation satisfy above-
mentioned conditions.
The separation must be more than 20 dB at
300Hz and 3kHz.
25
TH-42PA20U-P