Panasonic CT-1388YD, Service Manual

Page: 29 / 70

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Service adjustments (electronic controls, continued)
Sub-Brightness final adjustment
Service DAC (B03)
Perform this adjustment at the end. After all picture
adjustments.
Preparation:
1.
Turn the receiver ON and allow 20 min. warm up at
high brightness (white screen).
2. Apply a black-white cross pattern
3. Preset the following controls for best results:
• Picture . . . . . . Max
• Bright . . . . . . . Center
Procedure:
1.
In service mode, select sub bright register B02
2. Adjust register until get the 7.5 IRE section looks
the same light output than 3 Ire section,
(see Fig. 27)
Figure 28. Sub-bright adjustment
3. Exit Service Mode.
Horizontal centering
Service DAC (C09)
Preparation:
Connect a monoscope pattern.
Procedure:
1.
In the service mode select the horizontal centering
adjustment DAC (C09) and adjust until the center
of the pattern is centered on CRT. Distance A
should be same than B
Figure 29. Horizontal centering
2. Exit service mode.
Vertical size
Service DAC (C06)
Preparation:
Connect a monoscope pattern.
Procedure:
1.
In the service mode select vertical size adjustment
DAC (C06) and adjust until obtain a perfect round
picture.(Upper and lower section of the pattern
may go out of the visible are)
Figure 30. Vertical size
2. Exit the service mode.
MTS circuit adjustments
(stereo models only)
The MTS Circuit adjustments require two steps:
1.
Input level adjustment.
2. Stereo separation adjustment.
Input level adjustment (M00)
(stereo models only)
Preparation:
1.
Connect an RMS meter with filter jig as shown,
(see Fig. 30).
2. Connect an RF signal generator to the RF
antenna input.
Procedure:
1.
Apply the following signal from the RF signal
generator:
Video: 100 IRE flat field, 30% modulation.
Audio:
300Hz, 100% modulation, monaural
(70 ±5dB, 75
Ω
OPEN, P/S 10dB).
2. Adjust the MTS Input level adjustment (M00) until
the voltage measured is 106 ± 6.0mV rms.
3 IRE
7 IRE
B A
A=B
A
B
A B
~
~
10k
4700p
TPE11
RMS
METER
Figure 31. Filter jig