LG 42LH40 Diagram

P201 “SMPS" to P700 "Main PWB"

Run STBYLabelPin

2

PDIM24

3.2V0V

ncncnc23

0V0VErr Out22

21

1

A.DIM

1.66V0V

3.8V0VINV.ON20

ncncnc19

17,18

15,16

13,14

11,12

7,8,9,10

21.4V0V24V

GndGndGnd

12.3V0V12V

GndGndGnd

5.14V5.14V5V

GndGndGnd3,4,5,6

4.98V0VPWR-On2

ncncnc1

1

ADIM Pin 21 Fixed and not used

2

PDIM Pin 24 can vary according to type of signal

Diode

Check

Open

nc

Open

Open

2.25V

nc

0.81V

Gnd

1.2V

Gnd

2.85V

Gnd

1.19V

nc

being processed and the OSD Backlight setting.

0.6V 0% to 3.3V 100%. Output from the IC100.

R406 / R403

Bottom leg

48Khz

53V p/p

P1204 CONNECTOR "MAIN PWB" to J1 "Front IR / LED PWB

Switch Mode

Power Supply

From Hot Gnd

R406
R403

1.2KV

P402

1.2KV

P401

SMPS TEST 1: To Force Power Supply On.

Disconnect P700 on Main PWB.
Jump pin 7,8,9 or 10 (5V) to pin 2 using a 100Ω
resistor. (Test Voltage Outputs 12V, and 24V).

SMPS TEST 2: Jump pin 2 to pin 20 (INV-ON).
(Backlights and all voltages should turn on).

SMPS

250V 82mF

3.15A/250V
Run 380V

STBY 157V

T704

T703

F

5

0

1

250V 82mF

SK100

42LH40 INTERCONNECT DIAGRAM

TO TFT MODULE

23 24

P201

12

250V 82mF

250V 82mF

F100

6.3A/250V
AC IN

Tuner

F100

SK101

AC IN

Q701

Q705 Q704

P1200

P600

IC1003

Q702

P700

Q703

IC706

L607

L606

L1300

IC704

Q706

IC702

IC1002

L1301

D1403

L718

Q1202

IC601

D1402

L710

IC600

IC1300

D1401

D1400

IC701

IC1

IC105

IC104

D102

Q105 Q106

Q600

Pin 59 (-5V)
Pin 57 (26V)

IC705

L726

D1204

X100

12 Mhz

IC103

Micro Reset

SW100

P1401

IC100

Micro and

Video

Processor

Mstar

Pin 3,4,5 (16V)
Pin 7,8 (3.3V)

IC2

X1100

12 Mhz

IC101

IC502

IC501

D500

X1301

Q100

IC102

IC1200

Pin 56,57,58 (16V)

Pin 53,54 (3.3V)

IC1101

IC1100

Video

Processor

Tru-Motion

IC708

IC1000

Video Reset

SW1100

IC1201

IC1203

D1223

P1400

X1005
25Mhz

Q1000

Pin 2 (-5V)
Pin 4 (26V)

IC301

IC300

L712

IC1001

IC1004

8vsb/
QAM

TUNER

Q1001

IC707

LD1000

D1100

Q1100

Software

Upgrades

IC1202

LD1100

Video 19

SIF 16
(5V) 15

DIF - 13
DIF + 12

P1100

N/C

POWER On/Off

STBYLabel

3.29V

Diode CheckRun STBYLabelPin

Open3.3V3.3VSCL1

1.67V3.3V3.3VSDA2

GndGndGndGnd3

Side (Key) Controls

Main Power SW

MAIN (Digital) Board

Components that are Grayed out are on the back.

Q1200

(5V) 4

1

1.4V3.3V3.3VKey14

1.1V3.3V3.3VKey25

1.5V5.1V5.1V5V ST6

GndGndGndGnd7

GndGndGndGnd8

Open4.8V4.8VIR9

Front PWB

Assembly

P2

IR Receiver

Intelligent Sensor

GndGndGndGnd10

0.76V3.29V3.3V_ST11

Open3.29V0V12

P3000

P1

P2 "Front IR / LED PWB to P3000 Keys

Label

Key1

1

3.3V

Gnd

Key2

Gnd

Run STBYPin

3.3V

GndGnd2

3.3V3.3V3
GndGnd4

Diode

Check

Open

Gnd

Open

Gnd

Component Voltage on Next Page