Lg Rt-20la30 User manual

LCD TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS,

READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS : MF-002A

MODEL : RT-20LA30

website:http://biz.LGservice.com

e-mail:http://www.LGEservice.com/techsup.html

Dec.,2001

Printed in KoreaP/NO : 3828VD0090E

- 2 -

CONTENTS

Contents .................................................................................................. 2

Safety Precautions ..................................................................................3

Servicing Precautions ............................................................................ 4

Descriptions of Controls ........................................................................ 6

Adjustment Instruction ............................................................................9

Troubleshooting .....................................................................................18

Exploded View ...................................................................................... 20

Exploded View Parts List.......................................................................21

Replacement Parts List ........................................................................ 22

SVC. Sheet .................................................................................................

- 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 lsolation 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 circuitary 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 positioin, 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 esposed 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 sepcified, 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.

1.5 Kohm/10W

To Instrument's

exposed

METALLIC PARTS

Good Earth Ground

such as WATER PIPE,

CONDUIT etc.

AC Volt-meter

IMPORTANT SAFETY NOTICE

0.15uF

- 4 -

CAUTION: Before servicing receivers covered by this service

manual and its supplements and addenda, read and follow the

SAFETY PRECAUTIONS

on page 3 of this publication.

NOTE:

If unforeseen circumstances create conflict between the

following servicing precautions and any of the safety

precautions on page 3 of this publication, always follow the

safety precautions. Remember: Safety First.

General Servicing Precautions

1. Always unplug the receiver AC power cord from the AC

power source before;

a. Removing or reinstalling any component, circuit board

module or any other receiver assembly.

b. Disconnecting or reconnecting any receiver electrical plug

or other electrical connection.

c.

Connecting a test substitute in parallel with an electrolytic

capacitor in the receiver.

CAUTION: A wrong part substitution or incorrect

polarity installation of electrolytic capacitors may result

in an explosion hazard.

d. Discharging the picture tube anode.

2. Test high voltage only by measuring it with an appropriate

high voltage meter or other voltage measuring device (DVM,

FETVOM, etc) equipped with a suitable high voltage probe.

Do not test high voltage by "drawing an arc".

3. Discharge the picture tube anode only by (a) first connecting

one end of an insulated clip lead to the degaussing or kine

aquadag grounding system shield at the point where the

picture tube socket ground lead is connected, and then (b)

touch the other end of the insulated clip lead to the picture

tube anode button, using an insulating handle to avoid

personal contact with high voltage.

4. Do not spray chemicals on or near this receiver or any of its

assemblies.

5. Unless specified otherwise in this service manual, clean

electrical contacts only by applying the following mixture to

the contacts with a pipe cleaner, cotton-tipped stick or

comparable nonabrasive applicator; 10% (by volume)

Acetone and 90% (by volume) isopropyl alcohol (90%-99%

strength)

CAUTION: This is a flammable mixture.

Unless specified otherwise in this service manual, lubrication

of contacts in not required.

6. Do not defeat any plug/socket B+ voltage interlocks with

which receivers covered by this service manual might be

equipped.

7. Do not apply AC power to this instrument and/or any of its

electrical assemblies unless all solid-state device heat sinks

are correctly installed.

8. Always connect the test receiver ground lead to the

receiver chassis ground before connecting the test receiver

positive lead.

Always remove the test receiver ground lead last.

9.

Use with this receiver only the test fixtures specified in this

service manual.

CAUTION: Do not connect the test fixture ground strap to

any heatsink in this receiver.

Electrostatically Sensitive (ES) Devices

Some semiconductor (solid state) devices can be damaged

easily by static electricity. Such components commonly are

called

Electrostatically Sensitive (ES) Devices.

Examples of

typical ES devices are integrated circuits and some fieldeffect

transistors and semicounductor "chip" components. The

following techniques should be used to help reduce the

incidence of component damage caused by static by static

electricity.

1. Immediately before handling any semiconductor component

or semiconductor-equipped assembly, drain off any

electostatic charge on your body by touching a known earth

ground. Alternatively, obtain and wear a commercially

available discharging wrist strap device, which should be

removed to prevent potential shock reasons prior to

applying power to the unit under test.

2. After removing an electrical assembly equipped with ES

devices, place the assembly on a conductive surface such as

aluminum foil, to prevent electrostatic charge buildup or

exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or unsolder

ES devices.

4. Use only an anti-static type solder removal device. Some

solder removal devices not classified as "anti-static" can

generate electrical charges sufficent to demage ES devices.

5. Do not use freon-propelled chemicals. These can generate

electrical charges sufficient to damage ES devices.

6. Do not remove a repalcement ES device from its protective

package until immediately before you are ready to install it.

(Most replacement ES devices are packaged with leads

electrically shorted together by conductive foam, aluminum

foil or comparable conductive material).

7. Immediately before removing the protective material from

the ieads of a replacement ES device, touch the protective

material to the chassis or circuit assembly into which the

device will be installed.

CAUTION:Be sure no power is applied to the chassis or

circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged

replacement ES devices. (Otherwise harmless motion such

as the bruching together of your clothes fabric or the lifting

of your foot from a carpeted floor can generate static

electricity sufficient to damage an ES device.)

General Soldering Guidelines

1. Use a grounded-tip, low-wattage soldering iron and

appropriate tip size and shape that will maintan tip

temperature within the range or 500cF to 600cF.

2. Use an appropriate gauge of RMA resin-core solder

composed of 60 parts tin/40 parts lead.

3. Keep the soldering iron tip clean and well tinned.

4. Thorohly clean the surfaces to be soldered. Use a mall

wirebristle (0.5 inch, or 1.25cm) brush with a metal handle.

Do not use freon-propelled spray-on cleaners.

5. Use the following unsoldering technique

a. Allow the soldering iron tip to reach normal temperature.

(500cF to 600cF)

b. Heat the component lead until the solder melts.

c. Quickly draw the melted solder with an anti-static,

suction-type solder removal device or with solder braid.

CAUTION: Work quickly to avoid overheating the

circuiboard printed foil.

6. Use the following soldering technique.

a. Allow the soldering iron tip to reach a normal

temperature (500cF to 600cF)

b. First, hold the soldering iron tip and solder the strand

against the component lead until the solder melts.

SERVICING PRECAUTIONS

- 5 -

c. Qulckly move the soldering iron tip to the junction of the

component lead and the printed circuit foil, and hold it

there only until the solder flows onto and around both the

component lead and the foil.

CAUTION: Work quickly to avoid overheating the circuit

board printed foil.

d. Closely inspect the solder area and remove any excess

or splashed solder with a small wire-bristle brush.

IC Remove/Replacement

Some chassis circuit boards have slotted holes (oblong) through

which the IC leads are inserted and then bent flat against the

circuit foil. When holes are the slotted type, the following

technique should be used to remove and replace the IC. When

working with boards using the familiar round hole, use the

standard technique as outlined in parapraphs 5 and 6 above.

Removal

1. Desolder and straighten each IC lead in one operation by

gently prying up on the lead with the soldering iron tip as the

solder melts.

2. Draw away the melted solder with an anti-static suction-

type solder removal device (or with solder braid) before

removing the IC.

Replacement

1. Carefully insert the replacement IC in the circuit boare.

2. Carefully bend each IC lead against the circuit foil pad and

solder it.

3. Clean the soldered areas with a small wire-bristle brush.

(It is not necessary to reapply acrylic coating to the areas).

"Small-Signal" Discrete Transistor

Removal/Replacement

1. Remove the defective transistor by clipping its leads as

close as possible to the component body.

2. Bend into a "U" shape the end of each of three leads

remaining on the circuit board.

3. Bend into a "U" shape the replacement transistor leads.

4. Connect the replacement transistor leads to the

corresponding leads extending from the circuit board and

crimp the "U" with long nose pliers to insure metal to metal

contact then solder each connection.

Power Output, Transistor Device

Removal/Replacement

1. Heat and remove all solder from around the transistor leads.

2. Remove the heatsink mounting screw (if so equipped).

3. Carefully remove the transistor from the heat sink of the

circuit board.

4. Insert new transistor in the circuit board.

5. Solder each transistor lead, and clip off excess lead.

6. Replace heatsink.

Diode Removal/Replacement

1. Remove defective diode by clipping its leads as close as

possible to diode body.

2. Bend the two remaining leads perpendicula y to the circuit

board.

3. Observing diode polarity, wrap each lead of the new diode

around the corresponding lead on the circuit board.

4. Securely crimp each connection and solder it.

5. Inspect (on the circuit board copper side) the solder joints of

the two "original" leads. If they are not shiny, reheat them

and if necessary, apply additional solder.

Fuse and Conventional Resistor

Removal/Replacement

1. Clip each fuse or resistor lead at top of the circuit board

hollow stake.

2. Securely crimp the leads of replacement component around

notch at stake top.

3. Solder the connections.

CAUTION: Maintain original spacing between the replaced

component and adjacent components and the circuit board

to prevent excessive component temperatures.

Circuit Board Foil Repair

Excessive heat applied to the copper foil of any printed circuit

board will weaken the adhesive that bonds the foil to the circuit

board causing the foil to separate from or "lift-off" the board.

The following guidelines and procedures should be followed

whenever this condition is encountered.

At IC Connections

To repair a defective copper pattern at IC connections use the

following procedure to install a jumper wire on the copper

pattern side of the circuit board. (Use this technique only on IC

connections).

1. Carefully remove the damaged copper pattern with a sharp

knife. (Remove only as much copper as absolutely

necessary).

2. carefully scratch away the solder resist and acrylic coating

(if used) from the end of the remaining copper pattern.

3. Bend a small "U" in one end of a small gauge jumper wire and

carefully crimp it around the IC pin. Solder the IC connection.

4. Route the jumper wire along the path of the out-away

copper pattern and let it overlap the previously scraped end

of the good copper pattern. Solder the overlapped area and

clip off any excess jumper wire.

At Other Connections

Use the following technique to repair the defective copper

pattern at connections other than IC Pins. This technique

involoves the installation of a jumper wire on the component

side of the circuit board.

1. Remove the defective copper pattern with a sharp knife.

Remove at least 1/4 inch of copper, to ensure that a

hazardous condition will not exist if the jumper wire opens.

2. Trace along the copper pattern from both sides of the

pattern break and locate the nearest component that is

directly connected to the affected copper pattern.

3. Connect insulated 20-gauge jumper wire from the lead of

the nearest component on one side of the pattern break to

the lead of the nearest component on the other side.

Carefully crimp and solder the connections.

CAUTION: Be sure the insulated jumper wire is dressed so

the it does not touch components or sharp edges.

DESCRIPTION OF CONTROLS

- 6 -

0

231

564

897

POWER

MENU TV/AV

SLEEP

LIST

TEXT

MIX

INDEX

TIME REVEAL

SIZE HOLD UPDATE

I/II PSM

Q.VIEW

PR

OK

VOL VOL

PR

MUTE

MODE

M

i

All the functions can be controlled with the remote control handset.

Some functions can also be adjusted with the buttons on the front

panel of the set.

Remote control handset

Before you use the remote control handset, please install the bat-

teries. See the next page.

1. POWER

switches the set on from standby or off to standby.

2. NUMBER BUTTONS

switches the set on from standby or directly select a number.

3. MENU

selects a menu.

4. DD/ EE(Programme Up/Down)

selects a programme or a menu item.

switches the set on from standby.

FF/ GG(Volume Up/Down)

adjusts the volume.

adjusts menu settings.

OK

accepts your selection or displays the current mode.

5. Q.VIEW

returns to the previously viewed programme.

6. I/II

selects the language during dual language broadcast.

selects the sound output (option).

7. PSM (Picture Status Memory)

recalls your preferred picture setting.

1

2

3

4

5

6

7

- 7 -

8. MUTE

switches the sound on or off.

9. TV/AV

selects TV or AV monitor mode.

clears the menu from the screen.

switches the set on from standby.

10. SLEEP

sets the sleep timer.

11. LIST

displays the programme table.

12. TELETEXT BUTTONS (option)

These buttons are used for teletext.

For further details, see the ‘Teletext’ section.

Note : In teletext mode, the SLEEP,LIST and Q.VIEW buttons are

used for teletext function.

Battery installation

The remote control handset is powered by two AAA type batteries.

To load the batteries, turn the remote control handset over and

open the battery compartment. Install two batteries as indicated by

the polarity symbols ( and ) marked inside the compartment.

Note : To avoid damage from possible battery leakage, remove the

batteries if you do not plan to use the remote control handset for an

extended period of time.

+

-

0

2 31

5 64

8 97

POWER

MENU TV/AV

SLEEP

LIST

TEXT

MIX

INDEX

TIME REVEAL

SIZE HOLD UPDATE

I/II PSM

Q.VIEW

PR

OK

VOL VOL

PR

MUTE

MODE

M

i

8

12

10

11

9

- 8 -

1. MAIN POWER (ON/OFF)

switches the set on or off.

2. TV/AV

selects TV or AV monitor mode.

clears the menu from the screen.

switches the set on from standby.

3. MENU

selects a menu.

4. OK

accepts your selection or displays the current

mode.

5. FF/ GG(Volume Up/Down)

adjusts the volume.

adjusts menu settings.

6. DD/ EE(Programme Up/Down)

selects a programme or a menu item.

switches the set on from standby.

7. POWER/STANDBY INDICATOR (rr)

illuminates brightly when the set is in standby

mode.

dims when the set is switched on.

8. REMOTE CONTROL SENSOR

9. HEADPHONE SOCKET

Connect the headphone plug to this socket.

10. AUDIO/VIDEO IN SOCKETS (AV2)

Connect the audio/video out sockets of exter-

nal equipment to these sockets.

S-VIDEO/AUDIO IN SOCKETS (SAV)

Connect the video out socket of an S-VIDEO

VCR to the S-VIDEO socket.

Connects the audio out sockets of the S-

VIDEO VCR to the audio sockets as in AV2.

Back panel

6

Side panel

S-VIDEO VIDEO

MONO

AUDIO

L R

H/P

AV2

PR VOL OK MENU TV/AV

ON/OFF

5

4

3

2

1

7

8

RE/RL-20LA30 series

9 10

- 9 -

1. Application Object

This instruction is for the application to the LCD TV.

2. Notes

(1) This set uses an adapter, so connect the adapter and the

set correctly before adjustment.

(2) The adjustment must be performed under the correct

sequence.

(3) The adjustment must be performed in the circumstance of

25!5cC of temperature and 65!10% of relative humidity if

there is no specific designation.

(4) The input voltage of the receiver must keep 220V, 60Hz in

adjusting.

(5) The set must be operated for 30 minutes preliminarily

before adjustment if there is no specific designation.

[‘Heat Run’ must be performed with the full white signal or TV

noise signal in the internal part of the set.

[ The time for ‘Heat Run’ can be changed owing to production

plan.

3. Auto RGB Adjustment

3-1. Preparation for Adjustment

(1) Receive the Digital Pattern.

3-2. Adjustment

(1) Select AUTO RGB ADJ by pressing SVC Key of Remote

Control for Adjustment.

(2) Select “A RGB” Item.

(3) Press the VOL + Key to appear “OK”.

4. RGB LEVEL Adjustment

4-1. Using Equipment

(1) Pattern Generator(408NPS-READER) which 10 STEP is

possible.

(2) A Remote Control for Adjustment

4-2. Adjustment

(1) Select RGB LEVEL by pressing SVC Key of Remote

Control for Adjustment.

(2) Adjust that until 9th and 10th STEP is undistinguished by

using VOL +/- Key in R-LVL item.

(3) Adjust G-LVL and B-LVL as same way.

(4) When adjustment is finished, Store it by pressing OK key.

And escape it by pressing TV/AV Key.

5. Using method for CA-110

Use it in case of needing adjustment brightness.

6. OPTION Adjustment

(1) Press YELLOW button,or OP1,OP2,OP3 button on SVC

Remote Controller.

(2) INput data directly by the buttons corresponded with

OPTION 1 ???(0~255),OPTION 2 ??(0~63),OPTION3

???(0~255).

(3) Select each OPTION funtion by the CH Up/Down button.

Table 1. OPTION 1 Function

ADJUSTMENT INSTRUCTION

COLOR

ANALYZER:

CA110

30[cm]

LCD TV

Center of

Screen Input signal of Video

PAL BG 05 CH

NTSC 13 CH

0

1

0

1

0

1

0

1

0

1

0

1

0

1

2

3

SCART

A2 ST

SYS

TOP

I/II SA

TEXT

200 PR

Option Code Function Remark

100 PROGRAM SAVE

200 PROGRAM SAVE

Without TXT

With TXT

No Save DUAL SOUND Condition

Save DUAL SOUND Condition

FLOF TEXT

TOP TEXT

DVD JACK

SCART JACK

NICAM CHECK

NICAM&FM STEREO

B/G,I,D/K

B/G,L/L

B/G,I,D/K,M

RESERVED

- 10 -

OPTION

Data 200

PRO

TEXT

I/II SA TOP A2 ST SYS

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

SCART

0

1

0

1

0

1

OPTION

Data 200

PRO

TEXT

I/II SA TOP A2 ST SYS

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

SCART

1

0

1

0

1

0

1

- 11 -

OPTION

Data 200

PRO

TEXT

I/II SA TOP A2 ST SYS

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

SCART

1

0

1

0

1

0

1

OPTION

Data 200

PRO

TEXT

I/II SA TOP A2 ST SYS

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

SCART

1

0

1

0

1

0

- 12 -

OPTION

Data 200

PRO

TEXT

I/II SA TOP A2 ST SYS

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

SCART

1

0

1

0

1

0

OPTION

Data 200

PRO

TEXT

I/II SA TOP A2 ST SYS

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

1

0

1

0

1

0

1

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

0

1

2

3

SCART

0

1

0

1

Table 2. OPTION 2 Function

(1) English,German,French,Italia,Spanish

(2) English,Dutch,Swedish,Norwegian,Danish,Swiss,

Portuguess,Romanian,Polish,Hungarian,Czech,Russian

(3) English,French,Arab,Urdu

- 13 -

0

1

0

1

0

1

0

1

2

3

4

5

6

7

Austrailia

Defaut(0)

English

(1)

(2)

English,Farsi

(3)

English,China

ACMS

LANG

BBACK

VOL

Option Code Function Remark

Without ACMS funtion

With ACMS funtion

NORMAL Volume Curve

RUSHED Volume Curve

Without Blue Back

With Blue Back

English only

English+EU4

English+Other EU

FARSI

ARAB+URDU

ENGLISH+CHINA

RESERVED

ACMS

0

1

LANG

5

6

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

0

1

2

3

4

BBACK

0

1

0

1

0

1

VOL

1

0

1

DATA

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

ACMS

0

LANG

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

0

1

2

3

4

BBACK

0

1

0

VOL

0

1

DATA

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

Table 3. OPTION 3 Function

- 14 -

ACMS

1

LANG

4

5

6

7

BBACK

1

VOL

1

DATA

60

61

62

63

Defaut(0)

Teletext

Language

INVT

MD SA

MONO

CH+AU

T-LAN

IIC T

PANEL

TSS

KEY

Option Code

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

Function Remark

LOCAL KEY(20A20 MODEL)

LOCAL KEY(20LA30 MODEL)

Without TURBO SEARCH funtion

With TURBO SEARCH funtion

LCD PANEL OPTION

RESERVED

Tunning with AFT Voltage

Tunning with ADC of IF IC

INVERTER OPTION

RESERVED

Without LAST MODE SAVE

Witht LAST MODE SAVE

Without Forced MONO sound system

With Forced MONO sound system

Without D/K CHINA or BB system

With D/K CHINA or BB system

WEST Europe

EAST Europe

TURKEY

Czecho/Hungary

Cyrillic 1

Cyrillic 2

Cyrillic 3

Turkey/Greek 1

Turkey/Greek 2

Turkey/Greek 3

Arab/France

Arab/English

Arab/Hebrew 1

Arab/Hebrew 2

Farsi/English

Farsi/France

Farsi all

DATA KEY TSS

PANEL IIC T MD SA

CH+AU

MONO

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

INVT

0

1

0

1

0

1

- 15 -

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

DATA

KEY TSS

PANEL

IIC T

MD SA

CH+AU

MONO

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

INVT

1

0

1

0

1

0

1

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

DATA

KEY TSS

PANEL

IIC T

MD SA

CH+AU

MONO

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

INVT

1

0

1

0

1

0

1

- 16 -

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

DATA KEY

TSS

PANEL

IIC T

MD SA

CH+AU

MONO

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

INVT

1

0

1

0

1

0

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

DATA KEY

TSS

PANEL

IIC T

MD SA

CH+AU

MONO

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

INVT

0

1

0

1

0

1

0

- 17 -

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

DATA KEY

TSS

PANEL

IIC T

MD SA

CH+AU

MONO

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

INVT

0

1

0

1

Troubleshooting

- 18 -

4 No sound Defective Reset IC of IC902 1) Check volume and speaker

- Speaker Defective MSP3410D of IC901 - Sound comes out only when being inputted into Audio

- Earphone Defective B+(8V,5V) of IC903,904. L/R

2) Check after replacing IC902

3) Replace IC901

4) Check and replace B+ of IC903,904.

5 Video color beat noise Soldering IC201 and IC502,IC501 Check and resoldering.

or masking it short.

6 Video Jitter P501B Pin20 connector defective. Check the P501B Pin20 connector and repair.

1 No screen Input error of inverter connector 1) Bend the pin legs of P802B connector -> recheck

them

2) Check and repair the IC806,807 SI4925,IC801

SI786,IC803 SI4808.

P502 and Pin 21 connector 1) Check and fix P503B connector

being slipped out 2) Check and fix the components at P502 LCD module

and at main board.

3) Check Pin50.

Cracked components and 1) Check and repair tuner board and main board

soldering at tuner board 2) Solder Q101.

2 Dark screen 1) Defective LCD lamp 1) Replace the inverter

2) Defective inverter 2) Replace the LCD lamp

3) Input error of inverter connector 3) Check the connector input.

3 Broken OSD display Defective the font rom of IC501 Check and replace the font rom of IC508

1. General Features

No. Symptom Cause Check Point

Check Point

2. TV and external input

No. Symptom Cause

MEMO

- 19 -

- 20 -

EXPLODED VIEW

310

330

560

540

300 120

400 430

410

420

112

174

A4

530

570

520 550

LG RT-20LA30 User manual

Popular LCD TV manuals by other brands