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Service adjustments (electronic controls, continued)
Stereo separation adjustment
(M01 & M02) (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
(M02) 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
(M01) 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 see Fig. 31
signal
from
the
RF
- 30 -
7. Exit Service Mode. Turn off the set. Remove all
connections from chassis.
Clock adjustment
Service DAC (X03)
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
(X03).
3. Calculate
and
set
following formula:
=
128
+
0.90
X03
Note: TP5 measurement will not change
regardless of the value stored in X03.
Figure 32. Focus adjustment
).
the
decimal
point.
X03
based
on
the
{
}
(
)
6
Ð
TP
125
×10
-------------------------------- -
(
(
)
)
125
A
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