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Service Adjustments (Electronic Controls, cont.)
20. In the Serviceman 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 Serviceman 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 Serviceman
Mode and perform the Minor Touch – Up Method.
24. Perform Sub-Brightness Adjustment procedure if
needed.
Horizontal Centering
Serviceman DAC Adjustment (C9)
Preparation:
Connect a crosshatch generator.
Procedure:
1. In the Serviceman 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 Serviceman Adjustment Mode.
Audio Adjustment
Serviceman 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, 75Ω 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. 37.
RMS
METER
4700p
Figure 37. Filter Jig
Procedure:
1. In the Serviceman Mode for making electronic
adjustments, select the Audio Adjustment DAC
(B6) and adjust until 75mV RMS ± 7.5mV RMS is
measured.
2. EXIT the Serviceman Adjustment Mode.
MTS Circuit Adjustments
The MTS Circuit Adjustments require two steps:
1. Input Level Adjustment.
2. Stereo Separation Adjustment.
TPE1
(A-BOARD)
10k
Input Level Adjustment (M0)
Preparation:
1. Connect an RMS meter with filter jig as shown in
Fig. 38.
RMS
METER
4700p
Figure 38. Filter Jig
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,
(70 ±5dB, 75Ω 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:
Video: 100 IRE flat field, 30% modulation.
Audio: 300Hz, 100% modulation, stereo (left only)
(70 ±5dB, 75Ω OPEN, P/S 10dB).
3. Adjust the MTS Low-Level Separation Adjustment
(M2) until the amplitude displayed on the scope
is minimum.
4. Apply
the
following
signal generator:
Video: 100 IRE flat field, 30% modulation.
Audio: 3KHz, 100% modulation, stereo (left only)
(70 ±5dB, 75Ω OPEN, P/S 10dB).
5. Adjust the MTS High-Level Separation Adjustment
(M1) until the amplitude displayed on the scope is
minimum.
6. Repeat above steps 2 through 5 until the amplitude
is at minimum for both signals.
- 30 -
TPE10
10k
100%
modulation,
monaural
signal
from
the
RF
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