LG 55UF7600 Schematic

LG

M

y

2015 Direct View UHD Training

55UF7600 WebOS

2.0

UHD LCD TV

MAIN BOARD INFORMATION

ain Board Layout and

Voltage Measurements

55UF7600 Main Board (Photo)

55UF7600 (2015) Main Board Section

September 2016

Page 01

LG

55UF7600 Main Board Component Layout

P2300 "MAIN Board" to "SMPS Board" P201

LABELPIN STBY RUN Diode Check

23-24

18-22

GND GndGnd Gnd

24V OL0V 25.46V

16-17 GND GndGnd Gnd

11-15

9-10

7-8

6

5

4

3

2

1

12V OL0V 11.88V

GND GndGnd Gnd

3.5V 1.23V3.54V 3.52V

GND GndGnd Gnd

3.5V 1.23V

3.54V 3.52V

P-DIM2 0V OL0.92V

P-DIM

0.17V-2.55V

0V OL

DRV_ON 0V 3.46V 1.54V

PWR_ON 0V 3.51V OL

Dim to Bright

(1) PWR_ON: turns on the 12V and 24V lines.
Backlight power goes to 63.62V.
(2) INV_CTL: (DRV_ON on SMPS) turns on the
Backlights. Backlight power goes to 80V.
(3) P-DIM: controls the backlight brightness. Controlled
by Cust. Menu, Video, Backlights. Range 0% to
100% directly proportional to DC voltage to Backlight
brightness. P-DIM is actually a PWM signal.

(4) P-DIM2: Fixed Voltage.

KEY VOLAGES

P4100 "MAIN" to "Joy Stick J1, M-Remote/WiFi"

LABELPIN STBY RUN Diode Check

2

3.5V_WOL OL0V 3.49V

12 Key 1 1.98V3.55V 3.52V

14 Key 2 1.98V3.55V 3.52V

15 IR 1.89V3.54V 3.78V

16 3.5V_ST 1.25V3.56V 3.52V

Pin 2 is power for the M-Remote / WiFi Board
Pin 16 is power for the IR/Joy Stick Board
IR peak/peak 3.80V

September 2016

LD12900: Indicates VX1 Signal to
T-CON is good if LD12900 is illuminated.
If Off, possible causes:
Improper seated or defective Vx1 cable
or problem with signal processing.
LD12901 turned on by Q12900

Note: With top 3 screws left out of the
board, video looks double image like it's
in 3D.

Q402 M2_DDR_RESET_N

Q7100 I2C_SCL6 Buffer
Q7101 I2C_SDA6 Buffer

Q7102 HTPDAn Driver

Q7103 LOCKAn Driver
Q7104 HTPDAn Switch
Q7105 LOCKAn Switch

Q401 M1_DDR_RESET_N Select

WiFi pin 1

Joy Stick pin 2

Joy Stick pin 3

Joy Stick pin 7

Joy Stick pin 4

To the

T-CON

13.2V

Pins 48-51

IC2307 12V

PWR_Det

IC2300

+1.1V_VDDC_CPU

To

SMPS

Q2300

PWR_ON

X3000

(32.768KHz)

Q3001

CEC

SW3000

Micom Reset

All Speaker plug pins

(Min) 2.83V-3.20V (Max)

Diode Check (OL)

Page 02

LD12901

IC1901

SPI FLASH

DDR_VTT_URSA

P7100

IC2307

Panel_VCC

IC2309

IC2300

Q2321

P2300

3

X3000

IC3000

P3000

S

D

G

Q3001

SW3000

Q5800

B

E

C

+3.5V_WiFi

IC4100

P5800

Q12900

LD1900

EB

C

Q1901

DDR_VTT_1

IC2303

Q7101 FET

Q7100 FET
Q7102 Q7104
Q7103 Q7105

1

2

3

Q2301

+1.8V

1

Q2300

2

Micro

Mute

IC5800

Audio

B

C

E

IC2500

URSA9

IC2900

DDR

IC13100

Q402

+1.5V_DDR

IC600

IC602

D

Q2302

GS

IC402

In
Out

Adj

RS232

IC6801

JK3801

RS232

P4000

P4100

55UF7600 (2015) Main Board Section 08

X1900

(24MHz)

+1.5V_U_DDR

IC2800

DDR

IC13403

IC407

IC405 IC406

DDR

AVDD_3P3

Processor

DDR

DDR

Q2302 CPU_VID1 Select

Q401

C

DDR-VTT

E

B

IC401

IC2301

IC102

NVRAM

P101

IC6100

JK5000

LAN

JK3803

Head

Phone

MAIN BOARD

JK3802

To

Ft. Joy Stick /

IR

N/C

DDR

P1905

IC2600

DDR

IC2700

M13507

DDR

IC201

+3.5V_WOL

IC100

Q400

B

E

C

IC400

Head Phone Amp

Optical

JK3800

Heatsink Clip

IC13408

+1.1V_U_VDDC

CORE_VIDO Selector

D

Q2500

S

G

IC2501

CORE_VID1 Selector

D

Q2501

S

G

+1.1V_VDDC

Heatsink

Clip

+5V_Normal

+3.3V_Normal

3

1
2

IC200

X600

(24MHz)

USB_+5V

IC2305

IC2302

IC4300

+5V_USB_3

Q400 M0_DDR_RESET_N Select

IC8100

MEMC

/FRC

Main Board
p/n: EBT63818912 AUSYLJR
p/n: EAJ63109901 BUSYMJR
p/n: EAY63729101 BUSYLJR

p/n: EBT63990602 AUSYMJR
p/n: EBT63990603 AUSYMJR

TU_CVBS

TU6705

TDJH-H301F

Access Tuner

TUNER

pins from the

TU6401

back
side

Q6502

B

9

1

Q3300

C

E

Hot

Swap

JK4300

USB3 USB2 USB1

JK4302
JK4500

HDMI3 HDMI2 HDMI1

JK3203

JK3200

JK3202

B

C

E

TUNER PINS

9. CVBS

8. SIF

7. DIF (N)

6. DIF (P)

5. SDA_RF

4. SCL_RF

3. DIF AGC

2. N/C

1. +3.3V_LNA_TU

LG

55UF7600 Main Board Crystals Measurements

X1900

(24MHz)

X1900 Top Right Leg P/P

24Mhz 1.42VDC

1.35VDC

Bottom Left Leg

2.92V p/p

3.6V p/p

55UF7600 (2015) Main Board Section

Top Right

2.92V / 25nSec

Bottom Left

3.6V / 25nSec

X600 Top Left Leg

24Mhz 1.68VDC 3.72V p/p

X3000

X3000 Right Leg

0.68VDC

Left Leg

24Mhz 0.15VDC 856mV p/p

P/P

1.08mV p/p

X600

(24MHz)

1.70VDC

Bottom Right Leg

P/P

3.04V p/p

Top Left

3.04V / 10nSec

Bottom Right

3.72V / 10nSec

Right Leg

1.08V / 10uSec

Left Leg

856mV / 10uSec

Page 03September 2016

LG