LG CA-21M60E, Service Manual

- 11 -

Y 

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.

Y 

Test Equipment required

1.  RF signal generator (with pattern generator)
2.  DC Power Supply
3.  Multimeter (volt meter)
4.  Oscilloscope
5.  Color analyzer

:

RF AGC (Automatic Gain Control) Adjustment

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. 

:

Screen Voltage Adjustment

1)  Input the Color Bar Pattern into Antenna jack.
2)  Select CutOff of SVC-3 mode.
3)  Turn the screen control clockwise until the Horizontal line

is visible and turn it counterclockwise until the Horizontal
line is faintly visible.

:

Focus Adjustment

NOTE:

This adjustment should be performed after warming

up for 10 minutes.

1)  Input the Color Bar Pattern into Antenna jack.
2)  Adjust the Focus control of FBT for best overall focus.

:

VCO Adjustment

1)  Input Digital Pattern into Antenna jack.
2)  Select A-PIF of SVC-4 mode.
3) Press VOL

F

/

G

button and A-PIF will be changed 0 to 1

while the number of PIF-C is rolling.

4) When PIF-C stops rolling, A-PIF will be changed 1 to 0 and

VCO adjustment is finished.

Caution : 

Do not press the Volume button again in A-PIF mode

after adjustment is finished.

Adjustment

1. Connect RF signal (65dB

!

0.5dB) and turn on the TV.

2. Press OK buttons on TV set and Remote Controller at the

same time to get into SVC 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(

Y

) button to memorize the data.

1. To get into SVC mode

1) Press OK buttons on both TV set and Remote Control at

the same time.

2) Press Yellow button to select OPTION-1, OPTION-2,

OPTION-3 or OPTION-4.

3) Press PR 

E

/

D

button to select an adjustment.

4) Press VOL 

F

/

G

button to change the data.

2. To memorize the adjusted data into EEPROM 

Press OK button.

3. To get out from SVC mode

Press TV/AV or Power button.

Test Point 

: AGC TP (J17) 

Adjust

: Remote Control

Test Point 

: RK (Red Cathode of CPT Board)

Adjust 

: Screen Control of FBT

TUNER

AGC Voltage

Default AGC Data

6700VPV002A(LG C&D)

2.5 

!

0.1V

24

6700VPV002B(LG C&D)

3.0 

!

0.1V

24

Test Point 

: Observing Display

Adjust 

: Focus control of FBT

ADJUSTMENT