LG 21FG1AL, 21FG1RG, 21FG1RL, 21FG1RB, 21FG1RLX Service Manual

...

COLOR TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS : CW81A

MODEL : 21FG1AL/RG/RL/RB/RLG/

RLX

MODEL : 21FG1AL/RG/RL/RB/RLG/RLX

-T3/Z3

North/ Latin America http://aic.lgservice.com Europe/Africa http://eic.lgservice.com

Asia/Oceania http://biz.lgservice.com

Oct., 2008

Printed in ChinaP/NO : MFL42451205

Internal Use Only

- 2 -

CONTENTS

CONTENTS............................................................................................... 2

SAFETY PRECAUTIONS...........................................................................3

SPECIFICATIONS......................................................................................4

ADJUSTMENT ...........................................................................................6

TROUBLE SHOOTING ............................................................................14

BLOCK DIAGRAM...................................................................................18

PRINTED CIRCUIT BOARD ....................................................................19

EXPLODED VIEW....................................................................................20

LGE Internal Use Only

- 3 -

SAFETY PRECAUTIONS

Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the Schematic Diagram and Replacement Parts List. It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer.

General Guidance

An isolation Transformer should always be used during the servicing of a receiver whose chassis is not isolated from the AC power line. Use a transformer of adequate power rating as this protects the technician from accidents resulting in personal injury from electrical shocks.

It will also protect the receiver and it's components from being damaged by accidental shorts of the circuitry that may be inadvertently introduced during the service operation.

If any fuse (or Fusible Resistor) in this TV receiver is blown, replace it with the specified.

When replacing a high wattage resistor (Oxide Metal Film Resistor, over 1W), keep the resistor 10mm away from PCB.

Keep wires away from high voltage or high temperature parts.

Due to high vacuum and large surface area of picture tube, extreme care should be used in handling the Picture Tube. Do not lift the Picture tube by it's Neck.

X-RAY Radiation

Warning:

To determine the presence of high voltage, use an accurate high impedance HV meter.

Adjust brightness, color, contrast controls to minimum. Measure the high voltage. The meter reading should indicate

23.5 ± 1.5KV: 14-19 inch, 26 ± 1.5KV: 19-21 inch,

29.0 ± 1.5KV: 25-29 inch, 30.0 ± 1.5KV: 32 inch If the meter indication is out of tolerance, immediate service and correction is required to prevent the possibility of premature component failure.

Before returning the receiver to the customer,

always perform an AC leakage current check on the exposed metallic parts of the cabinet, such as antennas, terminals, etc., to be sure the set is safe to operate without damage of electrical shock.

Leakage Current Cold Check(Antenna Cold Check)

With the instrument AC plug removed from AC source, connect an electrical jumper across the two AC plug prongs. Place the AC switch in the on position, connect one lead of ohm-meter to the AC plug prongs tied together and touch other ohm-meter lead in turn to each exposed metallic parts such as antenna terminals, phone jacks, etc. If the exposed metallic part has a return path to the chassis, the measured resistance should be between 1MΩ and 5.2MΩ. When the exposed metal has no return path to the chassis the reading must be infinite. An other abnormality exists that must be corrected before the receiver is returned to the customer.

Leakage Current Hot Check (See below Figure)

Plug the AC cord directly into the AC outlet.

Do not use a line Isolation Transformer during this check.

Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor between a known good earth ground (Water Pipe, Conduit, etc.) and the exposed metallic parts. Measure the AC voltage across the resistor using AC voltmeter with 1000 ohms/volt or more sensitivity. Reverse plug the AC cord into the AC outlet and repeat AC voltage measurements for each exposed metallic part. Any voltage measured must not exceed 0.75 volt RMS which is corresponds to

0.5mA. In case any measurement is out of the limits specified, there is possibility of shock hazard and the set must be checked and repaired before it is returned to the customer.

Leakage Current Hot Check circuit

The source of X-RAY RADIATION in this TV receiver is the High Voltage Section and the Picture Tube. For continued X-RAY RADIATION protection, the replacement tube must be the same type tube as specified in the Replacement Parts List.

IMPORTANT SAFETY NOTICE

0.15uF

LGE Internal Use Only

AC Volt-meter

Good Earth Ground such as WATER PIPE,

To Instrument’s exposed METALLIC PARTS

CONDUIT etc.

1.5 Kohm/10W

Scope

This specification is applied to all the television related to CW 81A Chassis.

Requirement for Test

Each part is tested as below without special appointment.

1) Temperature : 25 ± 5°C (77 ± 9°F), CST : 40 ± 5

2) Relative Humidity : 65

± 10%

3) Power Voltage : Standard input Voltage AC220V ~ 50/60Hz. * Standard Voltage of each products is marked by models.

4) Specification and performance of each parts are followed each drawing and specification by part number in accordance with BOM.

5) The receiver must be operated for about 20 minutes prior to the adjustment.

Test Method

1) Performance : LGE TV test method followed.

2) Demanded other specification

- 4 -

General specification

SPECIFICATIONS

Note : Specification and others are subject to change without notice for improvement.

Item

Receiving System

Available Channel

Input Voltage

Market

Screen Size

Aspect Ratio Display Method Tuning System Operating Environment

Storage Environment

Specification

PAL BG, DK, I / NTSC M (AV 3.58/ 4.43) PAL BG, DK, I / NTSC M (AV 3.58/ 4.43) SECAM DK PAL NM / NTSC M (AV 3.58) PAL BG, DK, I / NTSC M (AV 3.58/ 4.43) SECAM BG, DK, L VHF : E2 ~ E12 UHF : E21 ~ E69 CATV : S1 ~ S20 HYPER : S21 ~ S41 AC220V ~ 50/60Hz AC100 ~ 240V, 50/60Hz Korea, Latin America, China, Indonesia, Philipines, Taiwan, Thai, Vietnam, Asia, Africa 14 ~ 21 inch (FLAT / Conventional) 21'' Superslim/Ultraslim 4 : 3 CRT FVS

1) Temp : 0 ~ 40 deg

2) Humidity : ~ 85 %

1) Temp : -20 ~ 60 deg

2) Humidity : ~ 90 %

Remark

China/ Indonesia/ Thai/ Vietnam CIS

L America/ Philippines/ Taiwan Asia/Middle East/ Africa

PAL Model

East Asia Others

PAL Model

No.

6 7 8 9

LGE Internal Use Only

Model

T3/Z3 Model

Market

PAL Model

Remark

Safety: CB Spec. (EN60065)

EMC: CE Spec (EN55020,

EN55013)

Appliance

- 5 -

Features and Function (For China. Indonesia, Vietnam, Thai, CIS / Middle East Asia, Africa)

LGE Internal Use Only

Item

Feature AV Input

AV Output Component

Key Local Key

Remocon

Channel Auto prog.

Manual Prog. edit Favorite

Picture PSM

User Control

Sound SSM

Treble/ Bass Turbo SND

Timer Clock

Off time On time Auto off

Special Language

Input Child lock

Etc. Sleep

Review

Specification

2 AV 1

1 Monitor out 1 Input (For component)

Power, Vol(

F, G), PR(E, D), MENU, OK

Turbo-Picture, Sound LG Code (NEC) System/ Storage/ Normal/ Turbo Storage/ System/ Channel/ Fine/ Search/ Name Copy/ Move/ Delete/ Skip 8 Channel Dynamic/ Standard/ Mild/ Game/ User Contrast/ Brightness/ Color Sharpness Tint (NTSC-M Only) ON/OFF Flat/ Music/ Movie/ Sports/ User 0 ~ 100 ON/ OFF

-- : --

-- : -- Off(On)

-- : -- Pr 1 VOL 30 Off (On) On/ Off English/ Indonesia/ Thai/ Vietnam TV/ AV/ Component On/ Off

Remark

Rear1,(CVBS,L,R)

Rear Rear (Y,Pb,Pr,DVD-L/R) 7EA/ Front Option

Tint: NTSC System only

option AV, RF Stereo Option AV, RF Stereo Option

East Asia

No.

1. Scope of Application

These instructions are applied to CW81A Chassis.

2. Notes

1) Because this is a cold chassis, it is not necessary to use an isolation transformer. However, operating it using a transformer between the power supply line and chassis input to prevent electric shock and to protect the test instrument.

2) All adjustment must be done in the correct sequence. However, for better productivity, it can be change in a prepermitted range.

3) Environment conditions : If not specified, it must be done in following conditions. Temperature : 25 ± 5°C Humidity: 65% ± 10%

4) Power supply of SET for PAL/SECAM

China/indonesia/Vietnam/CIS Market: AC100~240V±10%,

50/60Hz.

5) If not specified, the receiver must be operated for more than 20 minutes prior to the adjustment.

6) Signal : Received the standard color signal (65dB±1dBuV). PAL/SECAM

: LG standard signal means the digital pattern

PAL-B/G 05CH.

7) If not specified, APC ON is APC CLEAR (DYNAMIC)

3. AGC Voltage Adjustment

3-1. Necessary Instrument

- Digital Multi-meter: 1 set

- Max Input Current : Over 1A/ Max Input Voltage : 500Vdc

- Measurement Range : 10mV-100mVdc/ Accuracy : 0.03%

3-2. Adjustment Preparation

1) Input in the 75Ω cable 65dB(±1dB) LG standard signal.

2) Connect the multi-meter to J105 (AGC Check, Marking).

3-3. Adjustment

1) Press the “INSTART” key of factory remote control and

select “VP0 (RF AGC)” adjustment mode.

2) Press the VOL+/- (

F/ G) key until the multi-meter shows

reading as shown below.

3) CAUTION: Since the signal strength can be easily

changed by the condition of signal cable, you need to check the signal strength frequently in order to prevent error.

4. Screen Voltage Adjustment

4-1. Adjustment (Using Factory Remote Control)

1) Input in the 75Ω cable LG standard signal (Digital Pattern, 480NC).

2) Press the “ADJ’ key of factory remote control once to make the TV set display horizontal line.

3) Turn the screen volume on the FBT clockwise until the horizontal line is visible and turn it counterclockwise until horizontal line faintly visible. (Exit screen voltage adjustment by press “Enter(

A)” key of

factory remote control.)

5. Purity and Convergence Adjustment

5-1. Purity adjustment

(1) Adjustment Preparation

1) Receive Red Raster Pattern for purity adjustment (51CH).

2) Demagnetize the CPT and Cabinet with a degaussing coil.

(2) Adjustment

1) Pre-adjust the static convergence (STC) with the 4 and

6pole magnet.

2) If the horizontal Line is inline with CPT Mark, 2-Pole

magnet should direct 3-9 o’clock direction.

3) If not, direct 2-pole magnet handle toward 6-12 o’clock

direction and adjust the Horizontal Line to fall onto the mark opening the magnet at an angle.

4) Push the DY(deflection yoke) all the way to the CPT

funnel.

5) Turn the purity magnet(2-pole magnet) so that the “green”

color portion of left side and the “blue” color portion on the right side have equal amount of color.

6) Pull the DY slowly backward and fix it when the whole

screen becomes red. (The specified torque for fixing DY screw should be 10Kg/cm.)

5-2. Convergency Adjustment

(1) Necessary Instrument

1) Degaussing Coil

2) Convergency fixing instrument (Speical tools)

(2) Adjustment Preparation

1) Operate the unit at least 15 minutes before adjustment.

2) Using degaussing coil, remove the stains on CPT &

Cabinet.

3) Received the Cross Hatch Pattern of Convergence. (09ch)

4) Let the Contrast in normal luminance level

(3) Static Convergence (STC) Adjustment

1) Receive the Cross Hatch Pattern Convergence (09ch).

G R B

- 6 -

ADJUSTMENT

G R B

LGE Internal Use Only

6700NFNS11E 6700VS0002F 6700PF0006B 6870NB0026A 6700MF0014A 6700MF0018A 6700MF0018B 6700MF0018D 6700MF0018E

LGIT LGIT

SANYO

LGIT LGIT LGIT LGIT LGIT LGIT

2.15 ± 0.05V

3.0 ± 0.05V

2.3 ± 0.05V

2.15 ± 0.05V

2.3 ± 0.05V

2.5 ± 0.05V

2.4 ± 0.05V

2.5 ± 0.05V

65dBu 65dBu 65dBu 65dBu 65dBu 65dBu 65dBu 65dBu 65dBu

TAEA-H111F

TAEW-G002D

115-B-A86EL TAEA-J001F

TAEW-G013D

TAEA-G011D TAEA-G001D TAEA-G011D TAEA-G111D

Korea

PAL PAL

HITACHI

PAL

SECAM(CIS)

PAL PAL

SECAM(CIS)

Tuner P/N Maker AGC Vol Signal Tuner Spec. Remark

- 7 -

2) Before adjusting Static Convergence (STC), adjust the focus first seeing to it that the WHITE color picture quality is sharp enough.

3) Converge the RED vertical and BLUE vertical line in unity (same line) by changing the angle between the 2 tabs of 4-pole magnet.

4) Converge the RED horizontal and BLUE horizontal line in unity(same line) by turning the 2 tabs of the 4-pole magnet. At this time, do not change the angle between the 2 tabs.

5) Converge the R, G, B vertical line in unity (same line) by changing the angle between the 2 tabs of the 6-pole magnet.

6) Converge the R, G, B horizontal line in unity(same line) by turning the 2 tabs of the 6-pole magnet. At this time, do not change the angle between the 2 tabs.

(4) Dynamic Convergence (DYC) Adjustment

1) Y-axis Adjustment:

Adjust convergence of Y-axis (vertical) by moving the

deflection yoke (DY) left and right.

2) X-axis Adjustment:

Adjust convergence of X-axis (horizontal) by moving the

deflection yoke (DY) up and down.

6. White Balance Adjustment

6-1. Necessary Instrument

1) Automatic White Balance Meter (Low/High light Pattern generator)

2) CRTColor Analyzer, CA -100: 1 set

3) Factory Remote Control

6-2. Adjustment Preparation

Prior to this adjustment, the Screen Voltage adjustment should be finished.

6-3. Automatic adjustment

1) Adjust using Auto White Balance Meter.

2) Enter CPU OFF Mode by pressing “IN-START” & “MUTE” key of factor remote control in turn before adjustment. Exit CPU OFF mode by press the “MUTE” key of factory remote control after adjustment finished.

* In case there is excess RED color at screen voltage

adjustment, adjust it using “volume - (

F) key of factory remote

control until the RED color disappear.

6-4. Manual adjustment

1) Adjust using white Balance meter and factory remote control.

2) Enter white balance adjustment mode by pressing “INSTART” key of factory remote control.

3) Use the CH

D, CHE Key to choose adjustment item.

4) Use the VOL

F, VOLG Key to change item data.

5) Adjustment Procedure a. Make the picture luminance 45Ft-L by changing the

“CONTRAST” and “BRIGHTNESS”.

b. Adjust X data of High light with R-DRIVE and Y data of

high light with B-DRIVE to have the color temperature as shown below.

c. Make the picture luminance 4.5Ft-L by changing the

“CONTRAST” and “BRIGHTNESS”.

d. Adjust X data of low light with R-BIAS and Y data of low

light with B-BIAS to have the color temperature as shown below.

e. Repeat steps a~d until both low and high light have the

same readings as shown below.

7. Focus Voltage Adjustment

This adjustment must be done after operating the TV set receiver sufficiently.

7-1. Adjustment Preparation

Receive the LG standard pattern (PAL: Digital pattern, 480NC,13CH) and set the picture condition on “APC ON” (CLEAR) mode.

7-2. Adjustment

Turn the focus volume on the FBT upper direction to have the best focus vertical line (Fig. 1(a)) and horizontal line (Fig. 1(b)) as shown below.

8. SUB-BRIGHTNESS Adjustment

8-1.Sub brightness adjustment is unnecessary(Don't adjust). 8-2. Sub-Tint adjustment

This adjustment has to be done only if the picture has bad tint otherwise, it can be omitted if the picture has good tint.

1) Receive LG standard pattern signal (SMPTE, 2CH)

2) Set the picture condition on “APC ON” (CLEAR) mode.

3) Press the “ADJ” key of the factory remote control three times to enter to “SUB-TINT” adjustment mode.

4) Change the Sub-Tint data by pressing the VOL

F, VOLG

key until the upper and lower CYAN color becomes same color.

9. Deflection setting data adjustment

These adjustment will be done by automatic adjustment Equipment. For manual adjustment, it is also possible by the following procedure.

9-1. Adjustment Preparation

1) Deflection setting data adjustment can be done only with remote control.

2) Press “IN-START” key on factory remote control continuously to enter to Deflection Adjustment mode.

3) Press the CH

D, E key to select adjustment item.

Market Color Temperature X-AXIS Y-AXIS

ALL 13,000 268±5 273±5

<Fig. 1>

LGE Internal Use Only

(a)

(b)

+ 15 hidden pages