Panasonic CT20DC50B - 20" CLR TV/DVD COMBO, Руководство по обслуживанию

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period of 175V above DC ground is measured, as
indicated in Fig. 42.
9. Connect the scope to the RED Cathode (KR).
10. In Service Mode for making electronic adjustments,
select the RED CUTOFF DAC (C0).
11. Press the R-Tune key on the Remote
12. View the scope trace and adjust the Service Mode
DAC (C0) for the scanning period to be 175V
above DC ground. (See Fig. 42)
13. Connect the scope to the BLU Cathode (KB).
14. In Service Mode for making electronic adjustments,
select the BLU CUTOFF (C2).
15. Press the R-Tune key on the Remote.
16. View the scope trace and adjust the Service Mode
DAC (C2) for the scanning period to be 175V
above DC ground. (See Fig. 42)
17. Turn the Screen Control (part of FBT) slowly
clockwise until a color horizontal line appears.
18. With the other two colors Service Mode DAC
CUTOFF adjustments (C0) RED, (C2) BLU;
increase the colors to create a white horizontal line.
19. Confirm that a good gray scale is established by
viewing B/W color bar pattern.
20. In the Service Mode for making electronic
adjustments select the DAC DRIVE adjustments
(C3) RED, (C4) BLUE and adjust for warm white in
a white color bar pattern.
21. EXIT the Service Mode.
22. Adjust the Picture Menu Video Adjustments Bright
and Picture from low scale to high scale and check
Black and White tracking.
23. If correction is needed: Re-Enter the Service Mode
and perform the Minor Touch – Up Method.
24. Perform Sub-Brightness Adjustment procedure if
needed.
Horizontal Centering
Service DAC Adjustment (C9)
Preparation:
Connect a crosshatch generator.
Procedure:
1.
In the Service Mode for making electronic
adjustments. Select the Horizontal Centering
Adjustment DAC (C9) and adjust until the center of
the crosshatch pattern is centered on CRT.
2. EXIT the Service Adjustment Mode.
Audio Adjustment
Service DAC Adjustment (B6)
This adjustment is factory set and needs to be
performed only when IC002 or IC101 is replaced.
Preparation:
1.
Apply the following signal at the antenna (70dB
± 5dB, 75
:
open P/S 10dB): audio signal set to
monaural, 300Hz. 100% modulation; video input of
100 IRE flat field, 30% modulation.
2. Connect the RMS Meter with filter jig as shown in
Fig. 43.
Procedure:
1.
In the Service Mode for making electronic
adjustments, select the Audio Adjustment DAC
(B6) and adjust until 75mV ± 7.5mV RMS is
measured.
2. EXIT the Service Adjustment Mode.
MTS Circuit Adjustments
The MTS Circuit Adjustments require two steps:
1.
Input Level Adjustment.
2. Stereo Separation Adjustment.
Input Level Adjustment (M0)
Preparation:
1.
Connect an RMS meter with filter jig as shown in
Fig. 44.
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
:
OPEN, P/S 10dB).
2. Adjust the MTS Input Level Adjustment (M0) until
the voltage measured is 106 ± 6.0mV RMS.
Stereo Separation Adjustment (M1 & M2)
Preparation:
1. Connect an RF signal generator to the RF antenna
input.
2. Connect a scope to TPE10.
Procedure:
1.
Select Stereo Mode in Audio menu
2. Apply the following signal from the RF signal
generator:
Figure 42. Cathode Waveform, Adjustment
Waveform Detail
175V DC
0V DC
Figure 43. Filter Jig
TPE1
(A-BOARD)
TPE10
Figure 44. Filter Jig
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