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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 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.
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
signal
from
the
RF
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
Example: 000.0000
2. In Service Mode select the Clock Adjustment DAC
(X3).
3. Calculate
and
following formula:
X3
=
128
+
Note: TP5
measurement
regardless of the value stored in X3.
Figure 32. Focus Adjustment
- 30 -
).
the
decimal
point.
set
X3
based
on
{
}
(
)
6
–
TP
125
×10
0.90
------------------------------ -
(
(
)
)
125
will
not
change
A
the
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