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Service Adjustments (Electronic Controls, cont.)
Stereo Separation Adjustment (M1 & M2)
(Stereo Models only)
Preparation:
1. Connect an RF signal generator to the RF antenna
input.
2. Connect a scope between to TPE10 and cold
ground ( ).
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 from the RF
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.
7. Exit Service Mode. Turn off the set. Remove all
connections from chassis.
Clock Adjustment
Service DAC (X3)
Preparation:
Connect the frequency counter from TP5 (TPs port
close to tuner) to cold ground( ).
Note: Frequency Counter probe capacitance
should be 8pF or less.
Procedure:
1. Measure TP5 for the frequency of the waveform
and record the reading.
Note: Measurement must have at least four digits
of resolution following the decimal point.
Example: 000.0000
2. In Service Mode select the Clock Adjustment DAC
(X3).
3. Calculate and set X3 based on the
following formula:
Note: TP5 measurement will not change
regardless of the value stored in X3.
Service Adjustments (Mechanical Controls)
Focus (part of T551)
Preparation:
Apply a monoscope pattern.
Procedure:
1. Adjust the Focus VR, trying to get the better focus
as possible at the right side.
2. Confirm a correct focus at the center, then try to
adjust “A” in Fig. 32
Figure 32. Focus Adjustment
X3
128 0.90
6
×10
TP 125()–{}
125()()
-------------------------------+=
A
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