- 30 -
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, 75
Ω
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, 75
Ω
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
Содержание CT-20R6CE
Страница 55: ... 55 ...
Страница 56: ...Printed in USA K01032593CM0319 ...
