Mts Adjustment - Panasonic TC-20LB30 Service Manual

8.6.

MTS Adjustment

Caution:
MTS adjustment shall be after the aging of 30 minutes or longer.
8.6.1. RF Audio Input level Adjustment
Instrument name
1. Filter jig
2. RF signal generator
3. RMS voltage meter
1. Apply following RF signal at Antenna input.
VIDEO : Flat field, 30 % modulation
AUDIO : 300 Hz, 100 % modulation, monaural
(70 dB ± 5 dB, 75 W Open, P/S 10 dB)
Note:
Make sure 75 us PRE-EMPHASIS is off.
2. Enter into MTSIN (MTS) adjustment mode.
3. Adjust "MTSIN" data (Input level) until the RMS voltage meter indicates 106 mVrms ± 6 mVrms.
8.6.2. Stereo Separation Adjustment
Instrument name
1. RF signal generator
2. Oscilloscope
1. Select STEREO mode in the AUDIO Menu.
2. Set "Audio volume" DAC to "40".
3. Apply following RF signal at Antenna input.
VIDEO : Flat field, 30% modulation
AUDIO : 300Hz sine wave, 30% modulation, STEREO (LEFT only)
(70dB ± 5dB, 75 W OPEN, P/S 10dB)
Note:
After setting 30% modulation with PL SW and NR SW off, turn PL SW and NR SW on.
4. Enter into SEPAL (MTS) adjustment mode.
5. Adjust "SEPAL" data (Low-level separation) until the amplitude becomes minimum.
6. Apply following RF signal at Antenna input.
VIDEO : Flat field, 30% modulation
AUDIO : 3kHz sine wave, 30% modulation, STEREO (LEFT only)
(70dB ± 5dB, 75W OPEN, P/S 10dB)
Note:
After setting 30% modulation with PL SW and NR SW off, turn PL SW and NR SW on.
7. Enter into SEPAH (MTS) adjustment mode.
8. Adjust "SEPAH" data (High-level separation) until the amplitude of the waveform is minimum.
9. Repeat steps 3. to 8. until Low-level separation and High-level separation satisfy above-mentioned conditions.
10. After adjustment, set "Audio" volume "DAC" to "16".
Note:
The separation must be more than 20 dB at 300Hz and 3kHz.
Connection
TP3572 - GND
RF ANT. INPUT
Filter jig
Connection
RF ANT. INPUT
VIDEO2 R
VIDEO2 R (RCA jack)-GND
15
TC-20LB30
Remarks
Filter jig
Remarks