Adjustment - LG CE-21F66X Service Manual

¡ Safety Precautions
1. It is safe to adjust after using insulating transformer
between the power supply line and chassis input to
prevent the risk of electric shock and protect the
instrument.
2. Never disconnect leads while the TV receiver is on.
3. Don't short any portion of circuits while power is on.
4. The adjustment must be done by the correct appliances.
But this is changeable in view of productivity.
5. Unless otherwise noted, set the line voltage to 230Vac¡
10%, 50Hz.
6. The adjustment of TV should be performed afther warming
up for 15 minutes.
¡ Test Equipment required
1. Multimeter (volt meter)
2. Oscilloscope
3. 10:1 PROBE
4. Color Analyzer
¡ RF AGC (Automatic Gain Control) Adjustment
Test Point : AGC TP (J10)
Adjust : Remote Control
The RF AGC was aligned at the time of manufacture for
optimum performance over a wide range conditions.
Readjustment of RF AGC should not be necessary unless
unusual local conditions exist, such as ;
1) Channel interference in a CATV system.
2) Picture bending and/or color beats, which are unusually
due to excessive RF signal input when the receiver is too
close to a transmitting tower or when the receiver is
connected to an antenna distribution system where the RF
signal has been amplified. In this case, the input signal
should be attenuated (with pad or filter) to a satisfactory
level.
3) Picture noise caused by "broadcast noise" or weak signal.
If the broadcast is "clean" and the RF signal is at least
1mV (60dBu), the picture will be noise free in any area.
Adjusting RF AGC to one end of rotation will usually cause a
relatively poor signal to noise ratio;
Adjusting to the other end of rotation will usually cause a
degradation of over load capabilities resulting in color beats or
adjacent channel interference.

Adjustment

1. Connect RF signal (65dB¡ 0.2dB) and turn on the TV.
¡ Standard adjustment Channel
- EU 05 Ch. (f = 175.25MHz) : CE,CL,CF,CT
rf
- EU 41 Ch. (f = 631.25MHz) : CI
rf
2. Press OK buttons on TV set and Remote Controller at the
same time to get into SVC-0 mode.
3. Press Channel UP/DOWN button on the Remote Controller
several times to find AGC??.
4. Press Volume UP/DOWN button until the AGC Voltage is
the same as the Table below.
5. Press OK(¡Æ ) button to memorize the data.
ADJUSTMENT
Model
System
Tuner P/N
Marker
AGC Voltage
Model
System
Tuner P/N
Marker
AGC Voltage
¡ Screen Voltage Adjustment
Test Point
Adjust
1) Connect the probe of oscilloscope to the RK (Red
Cathode) of CPT Board.
2) Set the oscilloscope to 50V/div and 20Us/div and after
putting GND line upon the lowest grid line of the scope by
pressing GND button,enter into DC mode.
3) Tune the TV set to receive a PAL-B/G 05CH STANDARD
Picture(PAL I model: 41CH).
4) Adjust Screen Volume of FBT so that the waveform is the
same as below figure (DC 135¡ 3V).
¡ Focus Adjustment
Test Point
Adjust
1) Tune the TV set to receive a PAL 05CH.
2) Adjust the Focus Volume of FBT for best focus of A.
3) Repeat above step 2) for best overall focus.
- 11 -
CE-
B/G,D/K,I
6700VPF005D
LG Innotek
2.4¡ 0.05V
CF-
B/G,D/K,I
6700VPF009G(W/O TBS) 6700VPF009G(W/O TBS)
6700VPV002B(W/TBS)
LG Innotek
2.5¡ 0.05V
: RK (Red Cathode of CPT Board)
: Screen Volume of FBT
Horizontal
FlyBack Time
The waveform of Screen Voltage
: Observing Display
: Focus Volume of FBT
CL-
B/G,LL'
6700VPF005D
LG Innotek
2.4¡ 0.05V
CT-
B/G,D/K,I,M
6700VPV002B(W/TBS)
LG Innotek
2.5¡ 0.05V
Black level
140Vp-p
White level
GND for dc