Emerson Orion TC1972D, Service Manual

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ELECTRICAL ADJUSTMENTS
1. BEFORE MAKING ELECTRICAL
ADJUSTMENTS
Read and perform t h e s e adjustments when repairing
the circuits or replacing electrical parts or PCB
assemblies.
CAUTION
Use an isolation transformer when performing
any service on lhis chassis.
Before removing the anode cap. discharge
electricity because it contains high voltage
When removing a PCB or related component.
alter unfastening or changing a wire. be sure to
put the wire back in its original position.
Inferior silicon grease can damage IC’s and
transistors. When replacing IC’s and transistors.
use only specified silicon grease (YG6260M).
Remove all old silicon before applying new
silicon.
l-l:
Prepare the following
measurement
tools
for electrical
adjustments
1. Sweepmarker Generator
2. Oscilloscope
3. Digital Voltmeter
4. Color Bar Generator
2.
BASIC ADJUSTMENTS
2-1: VIF AND AFT
NOTE
Connect input and output terminals of the
sweepmarket generator to the circuit as shown
in Fig. 2-l-a. then adjust it.
SWEEPMARKER
GENERATOR OUTPUT
0.022.uF
SWEEPMARKER
GENERATOR TP
Fig. 2-1
1. Connect output terminal of the sweepmarker
generator to TP201. (Connect a 2.7K ohm
resistor between them.)
2. Connect input terminal of the sweepmarker
generator t o TP204.
3. Connect a 1OK ohm variable resistor to IF AGC
terminal (TP210). 12V line and ground. then
adjust to make the waveform of the
oscilloscope readable.
a
1OK ohm
12V
AGC TP210
4. Adjust L205 until the waveform marker (45.75MHz)
becomes as shown in Fig. 2-l-b.
5,
6.
7
8.
9
1 0
11
45.75MHz
Disconnect output terminal of the sweepmarker
generator from
TP201.
then connect it to TP
of the tuner pack.
Adjust tuner pack coil until the waveform
becomes as shown in Fig. 2-l-c.
41.24MHz
Disconnect the 10K ohm variable resistor
and 2.7K ohm resistor.
Disconnect input and output terminals of the
sweepmarker generator.
Connect the AFT adjustment oscillator (45.75MHzl
to TP, of the tuner pack through a 2.7K ohm
resistor.
Connect the digital voltmeter to TP206.
Adjust L 2 0 4 to find the point where the voltage
of TP206 changes dramatically. and adjust to
4.5VDC at that point.
2-2: BRIGHT, AGC,
TINT AND COLOR
On-Screen Display Adjustment
Insert the point o f a straightened paper clip into
the hole on, the remote control marked with an
arrow as shown in Fig. 2-2.
The adjustment mode display will appear as shown
in Fig. 2-3.
3