LG

2015 Direct View UHD Training

55UF7600 WebOS 2.0 UHD LCD TV
MAIN BOARD INFORMATION

Main Board Layout

y and
Voltage Measurements
55UF7600 Main Board (Photo) 55UF7600 (2015) Main Board Section

September 2016 Page 01

LG
 55UF7600 Main Board Component Layout 55UF7600 (2015) Main Board Section 08
Heatsink Clip
P2300 "MAIN Board" to "SMPS Board" P201 X1900
LD12900: Indicates VX1 Signal to (24MHz)
T-CON is good if LD12900 is illuminated. Q12900
IC13408
PIN LABEL STBY RUN Diode Check B
+1.1V_U_VDDC
If Off, possible causes:
C
LD12901 E

23-24 GND Gnd Gnd Gnd Improper seated or defective Vx1 cable IC1901 N/C
or problem with signal processing. LD1900
IC2500 DDR P1905
18-22 24V 0V 25.46V OL
B E

IC2600 CORE_VIDO Selector

LD12901 turned on by Q12900
URSA9
C D

Q1901 G S
Q2500
16-17 GND Gnd Gnd Gnd DDR
Note: With top 3 screws left out of the SPI FLASH IC2700
IC2501 CORE_VID1 Selector
11-15 12V 0V 11.88V OL board, video looks double image like it's +1.5V_U_DDR Q2501
D

IC2900 IC2800
in 3D.
G S

9-10 GND Gnd Gnd Gnd DDR DDR IC13403 +1.1V_VDDC

7-8 3.5V 3.54V 3.52V 1.23V

DDR_VTT_URSA
Heatsink
6 GND Gnd Gnd Gnd IC13100 Clip
IC407
5 3.5V 3.54V 3.52V 1.23V
Q402 M2_DDR_RESET_N
P7100 DDR_VTT_1 IC405 IC406 M13507 +5V_Normal
To the IC2303 Q402 DDR DDR +3.3V_Normal USB_+5V
4 P-DIM2 0V 0.92V OL IC201
T-CON 1
2
3
IC2305
Q7100 I2C_SCL6 Buffer
3 P-DIM 0V 0.17V-2.55V OL +1.5V_DDR AVDD_3P3 IC200
Q7101 I2C_SDA6 Buffer 13.2V IC2302
Q7102 HTPDAn Driver Pins 48-51 +3.5V_WOL
Q7101 FET
2 DRV_ON 0V 3.46V 1.54V Q7103 LOCKAn Driver Q7100 FET Processor X600
Q7104 HTPDAn Switch (24MHz)
Q7102 Q7104 IC4300
Q7105 LOCKAn Switch
1 PWR_ON 0V 3.51V OL Q7103 Q7105
+5V_USB_3
IC2307 12V
Dim to Bright PWR_Det IC2307
2

3
1
IC600 DDR IC100 JK4300

Panel_VCC

USB3
(1) PWR_ON: turns on the 12V and 24V lines.
Backlight power goes to 63.62V. IC2309 IC602 DDR
IC2300 Q2302 CPU_VID1 Select
(2) INV_CTL: (DRV_ON on SMPS) turns on the IC2300 Q401
Q400 Q400 M0_DDR_RESET_N Select
D

+1.1V_VDDC_CPU Q2301 Q2302

DDR-VTT
C

Backlights. Backlight power goes to 80V.

G S
Q2321 E B

IC8100

USB2
Q401 M1_DDR_RESET_N Select IC402 B E
C

(3) P-DIM: controls the backlight brightness. Controlled

IC401

IC400
by Cust. Menu, Video, Backlights. Range 0% to To P2300 In
MEMC
JK4302
+1.8V Out /FRC
SMPS IC2301 JK4500
100% directly proportional to DC voltage to Backlight
Adj

Q2300 3 1 Q2300 IC102

brightness. P-DIM is actually a PWM signal. Head Phone Amp

USB1
2

PWR_ON NVRAM
(4) P-DIM2: Fixed Voltage. X3000 RS232 P101 Main Board
X3000

P3000
IC6100 Optical p/n: EBT63818912 AUSYLJR
(32.768KHz) IC3000 p/n: EAJ63109901 BUSYMJR
KEY VOLAGES IC6801 JK5000 JK3803 JK3800
Q3001 D
S
G
p/n: EAY63729101 BUSYLJR
P4100 "MAIN" to "Joy Stick J1, M-Remote/WiFi" CEC Q3001 LAN
p/n: EBT63990602 AUSYMJR
Micro

HDMI3
SW3000 p/n: EBT63990603 AUSYMJR
PIN LABEL STBY RUN Diode Check Micom Reset SW3000 JK3801
Head
Q5800 Mute RS232
2 3.5V_WOL 0V 3.49V OL WiFi pin 1 E B
Phone JK3203

C TUNER PINS
12 Key 1 3.55V 3.52V 1.98V Joy Stick pin 2 IC5800 TU_CVBS
9. CVBS

HDMI2
Audio MAIN BOARD Q6502 8. SIF
14 Key 2 3.55V 3.52V 1.98V Joy Stick pin 3 TU6705 C

7. DIF (N)
B E

9 JK3200 6. DIF (P)

15 IR 3.54V 3.78V 1.89V Joy Stick pin 7 +3.5V_WiFi
TDJH-H301F
TUNER
Access Tuner JK3202 5. SDA_RF
pins from the 1 Hot 4. SCL_RF
16 3.5V_ST 3.56V 3.52V 1.25V Joy Stick pin 4 IC4100 TU6401
back
Swap

HDMI1
side 3. DIF AGC

Pin 2 is power for the M-Remote / WiFi Board

P5800 JK3802
B

E
C
2. N/C
1. +3.3V_LNA_TU
Q3300
Pin 16 is power for the IR/Joy Stick Board P4100
P4000
IR peak/peak 3.80V
All Speaker plug pins To
(Min) 2.83V-3.20V (Max) Ft. Joy Stick /
Diode Check (OL) IR
September 2016 Page 02 LG
 55UF7600 Main Board Crystals Measurements 55UF7600 (2015) Main Board Section

X1900
(24MHz)
Top Right
2.92V / 25nSec
X1900 Top Right Leg P/P

1.35VDC 2.92V p/p

Bottom Left Leg Bottom Left

3.6V / 25nSec
24Mhz 1.42VDC 3.6V p/p

X600 Top Left

(24MHz) 3.04V / 10nSec

X600 Top Left Leg P/P Bottom Right

3.72V / 10nSec
1.70VDC 3.04V p/p

Bottom Right Leg

24Mhz 1.68VDC 3.72V p/p

Right Leg
X3000 1.08V / 10uSec

X3000 Right Leg P/P

Left Leg
0.68VDC 1.08mV p/p 856mV / 10uSec
Left Leg

24Mhz 0.15VDC 856mV p/p

September 2016 Page 03 LG

 55UF7600 (2015) Main Board Section
55UF7600 Main Board (Small) Component Voltages

Pin Memory Pin Regulator Pin Regulator Pin LD1900 Pin Driver
[1] Gnd [1] Gnd [1] 3.49V (Out) [E] 0.67V [B] 0V
[2] Gnd [2] 11.85V (Vcc In) [2] Gnd [B] 0.52V [C] 3.29V
[3] Gnd [3] Gnd [3] 0.43V (n/c) [C] Gnd [E] Gnd
[4] Gnd [4] 0.80V (FB) [4] 3.51V (En)
[5] 3.30V [5] 1.36V (Comp) [5] 3.51V (Vcc In) Q2300 PWR_On Q6502 TU_CVBS
[6] 3.30V [6] 3.47V (Enable) Pin Switch Pin Buffer
[7] Gnd [7] 1.07V (Out) IC4300 +5V_USB_1 [1] 3.50V [B] 1.52V
[8] 3.30V [8] 1.07V (Out) Pin Regulator [2] 2.84V [C] Gnd
[1] 5.11V (In) [3] 3.49V [E] 2.23V
IC200 +3.5V_WOL IC2301 +1.8V_DDR [2] Gnd
Pin Regulator Pin Regulator [3] 3.28V (Enable) Q2301 CPU_VID0 Q7100 I2C_SCL6
[1] 3.49V (Out) [In] 3.29V (In) [4] 3.30V (USB_OCD3) Pin Select Pin Switch
[2] Gnd [Out] 1.79V (Out) [5] 0.40V [G] 0.31V [G] 3.05V
[3] 0.17V n/c [Adj] 0.54V [6] 5.11V (Out) [S] Gnd [S] 3.27V
[4] 3.51V (WOL_CTL) [D] 0.07V [D] 3.26V
[5] 3.50V (Vcc In) IC2302 (+3.3V_NORMAL) IC13100 DDR_VTT_URSA
Pin Regulator Pin Regulator Q2302 CPU_VID1 Q7101 I2C_SDA6
IC201 AVDD_3P3 [1] Gnd [1] 1.52V (In) Pin Select Pin Switch
Pin Regulator [2] 11.82V (Vcc In) [2] Gnd [G] 3.29V [G] 3.05V
[1] Gnd [3] Gnd [3] 0.76V [S] Gnd [S] 3.27V
[2] 3.31V (Out) [4] 0.70V (FB) [4] 0.76V (Out) [D] 0.07V [D] 3.26V
[3] 3.50V (In) [5] 1.97V (Comp) [5] n/c
[6] 3.47V (Enable) [6] 3.29V (Enable) Q2321 Driver for Q7102 HTPDAn
IC402 DDR_VTT [7] 3.31V (Out) [7] n/c Pin IC2309 Pin Driver
Pin Switch [8] 3.31V (Out) [8] n/c [B] 0.66V [G] 0.18V
[1] 1.51V (in) [E] Gnd [S] 0.0V
[2] Gnd IC2303 +1.5V_DDR IC13403 (+1.5V_U_DDR) [C] 0.60V [D] 1.96V
[3] 0.76V Pin Regulator Pin Regulator
[4] 0.76V (out) [1] 3.40V (Enable) [1] 3.49V (Enable) Q2500 CORE_VIDO Q7103 LOCKAn
[5] n/c [2] 0.76V [2] 0.77V Pin Select Pin Driver
[6] 3.29V (Enable) [3] 5.23V [3] 5.23V [G] 3.31V [G] 0.18V
[7] n/c [4] 2.49V [4] 2.51V [S] Gnd [S] 0.0V
[8] n/c [5] Gnd [5] Gnd [D] 0.07V [D] 1.97V
[6] 1.57V (Out) [6] 1.53V (Out)
IC407 DDR_VTT_1 [7] 6.60V [7] 6.47V Q2501 CORE_VID1 Q7104 HTPDAn
Pin Switch [8] 11.84V (Vcc In) [8] 11.84V (In) Pin Select Pin Switch
[1] 1.52V (in) [G] 3.31V [G] 0.63V
[2] Gnd IC2307 PWR_Det Q400 M0_DDR_RESET_N [S] Gnd [S] 0.0V
[3] 0.76V Pin 12V Sense Pin Select [D] 0.07V [D] 0.04V
[4] 0.76V (out) [1] Gnd [E] Gnd
[5] n/c [2] 3.61V (Out) [B] 0.0V Q3001 CEC Q7105 LOCKAn
[6] 3.29V (Enable) [3] 3.64V (In) [C] Do Not Measure Pin Bi-Directional Pin Switch
[7] n/c [G] 3.51V [G] 0.0V
[8] n/c Q2309 Panel_VCC Q401 M1_DDR_RESET_N [S] 3.48V [S] 0.64V
Pin Switch Pin Select [D] 3.43V [D] 0.05V
IC1901 SPI FLASH [1] 11.85V (Vcc In) [E] Gnd
Pin Memory [2] 11.85V (Vcc In) [B] 0.64V Q3300 HDMI Q12900 Drives
[1] 3.29V (CS) [3] 11.85V (Vcc In) [C] 0.07V Pin Hot Swap Pin LD12901
[2] 3.28V (SO) [4] 1.86V (CTL) [B] 0V [E] 0.63V
[3] 0V (WP) [5] 11.84V (Out) Q402 M2_DDR_RESET_N [E] Gnd [B] 0.02V
[4] Gnd [6] 11.84V (Out) Pin Select [C] 0.63V [C] Gnd
[5] 3.29V (SPI_DI) [7] 11.84V (Out) [E] Gnd
[6] 0V (SPI_CK) [8] 11.84V (Out) [B] 0.0V
[7] 3.29V (Hold) [C] 1.56V
[8] 3.29V (In)

September 2016 Page 04

 55UF7600 (2015) Main Board Section
55UF7600 Main Board (Large) Component Voltages

IC2305 IC3000 IC5800

+5V_NORMAL / +5V_USB Micro Audio
Regulator Pin Processor Pin Pin Amp Pin
Pin Pin [1] 3.23V [25] 0V [1] n/c [21] 2.16V (Out R+)
[1] 25.35V (In) [15] 3.43V (OCP2) [2] 3.23V [26] 3.51V [2] 1.24V [22] Gnd
[2] 25.35V (In) [16] 5.11V [3] 2.69V [27] 3.51V [3] n/c [23] 4.71V
[3] 25.35V (In) [17] 5.11V [4] 2.09V [28] 0.03V [4] Gnd [24] 5.12V
[4] Gnd [18] 11.53V [5] 3.46V [29] 0.1V [5] n/c [25] 5.14V
[5] Gnd [19] 5.11V (Out) [6] 3.5V [30] 0V [6] 1.26V [26] n/c
[6] Gnd [20] 5.11V (Out) [7] 3.49V [31] 3.34V [7] 0V [27] 5.11V
[7] 6.30V [21] 5.11V (Out) [8] 3.51V [32] 3.51V [8] 1.62V [28] 4.72V
[8] 6.30V [22] 1.94V [9] 0V [33] 3.51V [9] n/c [29] Gnd
[9] 3.51V (Enable) [23] 0.60V [10] 3.51V [34] 3.75V [10] 2.62V [30] 2.16V (Out L-)
[10] 5.10V (Out USB2) [24] 0.35V [11] 3.51V [35] 0V [11] 2.43V [31-32] 18.67V (L B+)
[11] 5.10V (Out USB3) [25] 1.24V [12] 0V [36] 0V [12] 3.30V (Mute) [33] 2.16V (Out L+)
[12] 3.28V (USB2 Ctrl) [26] 0.45V [13] 3.51V [37] 0.02V [13] n/c [34] Gnd
[13] 3.28V (USB3 Ctrl) [27] 0.45V [14] 3.72V [38] 0V [14] 0.0V [35] 4.71V
[14] 3.43V (OCP2) [28] Gnd [15] 3.53V [39] 3.51V [15] n/c [36] 3.03V (Reset)
[16] 0V [40] 3.51V [16] 4.71V [37] Gnd
IC2501 [17] 3.51V [41] 0.65V [17] Gnd [38] 1.61V
+1.1V_VDDC [18] 3.51V [42] 0.13V [18] 2.16V (Out R-) [39] Gnd
Pin Regulator [19] 3.29V [43] 0V [19-20] 18.67V (R B+) [40] 3.31V (In)
[1] 3.51V (EN) [9] 11.83V (In) [20] 3.09V [44] 0.14V
[2] 0 43V (Freq)
0.43V [10] Gnd [21] 3 06V
3.06V [45] 0V
[3] 0.63V (FB) [11] Gnd [22] 0V [46] 2.09V IC13408
[4] 4.84V (SS) [12] Gnd [23] 0V [47] Gnd +1.1V_U_VDDC
[5] Gnd [13] Gnd [24] 0.1V [48] 3.51V Pin Regulator
[6] 4.83V (PG) [14] 11.83V (In) [1] 3.51V (EN) [9] 11.83V (12V In)
[7] 4.87V (VCC) [15] 1.02V (Out) IC6801 [2] 0.43V (Freq) [10] Gnd
[8] 5.79V (BST) [16] 1.02V (Out) RS232 [3] 0.63V (FB) [11] Gnd
Pin Data [4] 4.84V (SS) [12] Gnd
IC6100 [1] 3.52V [9] n/c [5] Gnd [13] Gnd
Head Phone [2] 5.39V [10] n/c [6] 4.83V (PG) [14] 11.83V (12V In)
Pin Amp Pin [3] 0V [11] 3.09V [7] 4.87V (VCC) [15] 1.18V (Out)
[1] Gnd [8] 1.66V [4] 0.02V [12] 3.52V [8] 5.95V (BST) [16] 1.18V (Out)
[2] 0V (R In) [9] 3.31V (3.3V_Normal In) [5] (-5.33V) [13] 0V
[3] 0V (R Out) [10] Gnd [6] (-5.34V) [14] (-5.24V)
[4] Gnd [11] n/c [7] n/c [15] Gnd
[5] 3.49V (Mute) [12] 0V (L Out) [8] n/c [16] 3.52V (3.5V_ST In)
[6] (-3.18V) [13] 0V (L In)
[7] (-1.59V) [14] Gnd

September 2016 Page 05

LG
2015 Direct View UHD Training
55UF7600 WebOS 2.0 UHD LCD TV
POWER SUPPLY BOARD INFORMATION

SMPS Board Layout

y and
Voltage Measurements
55UF7600 Power Supply Board Component Layout 55UF7600 (2015) Power Supply Section
P201 "SMPS Board" to P2300 "MAIN Board"
SMPS BOARD PIN LABEL STBY RUN Diode
P801 Black "SMPS Board" to the "Backlights" p/n: EAY63729101 28 *V_SYNC 0V 0.02V OL
PIN LABEL RUN Diode To
Backlights 27 *SIN 0V 0.05V OL
1 VC_6 7.30V-26.72V OL EL85
2 VC_5 7.20V-26.93V OL EL84
+25.36V
P801 P802 EL85 EL87 EL91
26 *Gnd Gnd Gnd Gnd
Gnd LED+ EL84 EL86 EL90
3 VC_4 7.36V-26.77V OL EL86 P203 P202 100uF/ 25 *SCLK 0V 0.04V OL
4 N.C. n/c n/c D253 D254
120V P702
23-24 Gnd Gnd Gnd Gnd
+79.8V
5 N.C. n/c n/c D261 18-22 24V 0V 25.46V 1.11V
T101 T102 +48.75V
LD701
6 n/c n/c n/c
N.C
D252 See Note 2
Normal: Off
16-17 Gnd Gnd Gnd Gnd
7 N.C. n/c n/c
11-15 12V 0V 11.88V 0.34V
8 LED+ 79.5V-79.9V OL P202 +49.02V
Bright (100%) to *Dim (0%)
D251 9-10 Gnd Gnd Gnd Gnd
+48.98V
Stby: 354V D252 L202 P201 7-8 3.5V 3.54V 3.52V 1.74V
F101

100uF/

100uF/
P802 White "SMPS Board" to the "Backlights"

100V

100V
Run: 393V 6 Gnd Gnd Gnd Gnd
C271 C251
PIN LABEL RUN Diode
D255 +11.96V
To 5 3.5V 3.54V 3.52V 1.74V
1 LED+ 79.5V-79.9V OL P202 Main/T-CON
82uF/460V

82uF/460V

4 (4) P-DIM2 0V 0.92V OL

2 N.C. n/c n/c D256 +11.96V
3 N.C. n/c n/c
Q102 Q103 3 (3) P-DIM 0V 0.17V~2.55V OL
4
3.15A / 250V IC102 2 DRV_ON 0V 3.46V OL
N.C n/c n/c
P100 L201
5 N.C. n/c n/c n/c Secondary 1 PWR_ON 0V 3.51V OL
6 VC_3 7.37V-27.16V OL EL90 Primary (3) Dim to Bright (4) Fixed
D601
7 VC_2 7.22V-26.94V OL EL87
LF102 LF101 Note: Main board only has 24 pins.
8 VC_1 7.60V-27.03V OL EL91
L601 105.2V BD101
(Top 4 are for local dimming from the T-CON).
D602
Bright (100%) to *Dim (0%) F100 PWR_ON Pin 1: Turns on 12V and 24V
392V D603 VA101 (Also see Note 1)
HGnd 5A / DRV_ON Pin 2: Turns on Backlights.
104V N L 250V (Also see Note 2) DRV_ON is
INV_CTL from Main.
E P-DIM Pin 3: Controls Backlights via customer’s menu
See Backlight Section concerning Backlights 0% to 100%.
P-DIM2 Pin 4: Fixed Voltage.
“Testing a Backlight Block VC_1-VC_6”
to confirm if the problems is the SMPS VOLTAGE LABEL SK100 Note 1: Backlight power is 63.62V with PWR_ON arrives, (no
or the Panel. MODEL LGP4955-15UL6 AC backlights)
This Screw is a
INPUT AC 100V~240V~50/60Hz. 2.8A Note 2: Backlight Power goes to 80V when DRV_ON arrives,
different size
IC102 3.5V = 1.7A 63.3V = 1.08A (49) M4 * L9 w/washer Backlights On).
OUTPUT
31V 6.56V 12V = 3.5A 72.6V = 1.08A (55)
LD701 normal state is Off. If it is blinking, it indicates a
Hot Gnd Chassis 24V = 1.2A
problem. Missing DRV_ON, LED feedback error, Controller
0.89V 7.60V Error, etc….
Example: If either P801 or P802 is disconnected, backlights
come on, but only ½ the screen is lit, then LD701 blinks 3
Note: Sometimes LD701 blinks during times every 5 seconds. If DRV_ON is missing,
normal start-up (7 times). Local LD701 (after 1 minute), blinks 5 times every 5 seconds.
Dimming Error Code.

September 2016 Page 01 LG

55UF7600 Power Supply Board Voltage Information 55UF7600 (2015) Power Supply Section
P201 "SMPS Board" Stand-Alone
LED Power during TEST 1. 63.62V After 1 minute LD701 Red LED Blinks 5 times every 5 seconds
Pin Label Test 1 Test 2
Test 1 LED Ground Return Line 12.35V Average: Backlights are not on
28 *Vsync n/a n/a
LED Power during TEST 2. 76.2V LD701 does not blink
27 *SCLK n/a n/a
Test 2 LED Ground Return Line 1.17V Average: Each varies due to brightness uniformity software
26 *Gnd n/a n/a SMPS Controller IC is IC101
(1) PWR_ON turns on the 12V and 24V lines. Backlight power
25 *SCLK n/a n/a Backlight Driver IC is IC801 approx. 63.62V.

23-24 Gnd Gnd Gnd Backlight Controller IC is IC701 (2) DRV_ON (INV_ON from Main) turns on the Backlights.
Backlight power goes to approx. 80V.
24.50V 24.65V D251 3.5V_ST Source (back of the board)
18-22 24V
D252 D261 24V Source (3) P_DIM controls the backlight brightness. Controlled via the
16-17 Gnd Gnd Gnd Customer’s Menu: Home Settings Picture Backlights.
D253 D254 D255 12V Source Range 0% to 100% directly proportional to DC voltage to Backlight
11-15 12V 12.07V 12.04V brightness. (0.17V~2.55V)
D259 D263 Backlight Power Source P_DIM is actually a 4V p/p PWM signal.
9-10 Gnd Gnd Gnd P201 "SMPS Board" With Smart Jig
(4) P_DIM2 fixed voltage.
7-8 3.5V 3.54V 3.53V Pin Label W/Jig

Gnd Gnd 28 *Vsync n/c

6 Gnd LED Power during Jig Test 75.7V LD701 does not blink
27 *SCLK n/c
5 3.5V 3.54V 3.53V Test 2 LED Ground Return Line 0.97V-1.45V Each varies due to brightness unifo
26 *Gnd n/c
(3) SMPS Controller IC is IC100
4 P-DIM2 3.52V 3.50V
25 *SCLK n/c
Backlight Driver IC is IC801
(3) 3.52V 3.50V
3 P-DIM 23-24 Gnd Gnd Backlight Controller IC is IC701

2 (2)
DRV-ON 0V 3.53V 18-22 24V 24.72V D203 3.5V_ST Source

(1) 16-17 Gnd Gnd D251 D252 24V Source

1 PWR-ON 3.54V 3.53V
11-15 12V 12.04V D255 D256 D255 12V Source
BL Off BL On D210 (D251) Backlight Power Source
9-10 Gnd Gnd

7-8 3.5V 3.51V

If P801 is disconnected, the backlight power will start at 37.7V, Additional Details:
then jump to 47.97V and then fall back to 47.87V. Warning: 6 Gnd Gnd 11.18V Average voltage swing for a block of LEDs. V1-V6
Backlight power is slow to bleed down after power off, connected 3.51V
1.17V Average Feedback Voltage (High Bright)
5 3.5V
or disconnected. 12.35V Average Feedback Voltage (Dim)
If P801 is disconnected, Front Right half LEDs stay on. 4 (3)
P-DIM2 n/c 79.5V Backlight power 100% Backlights
If P802 is disconnected, Front Left half LEDs stay on. 79.9V Backlight power 0% Backlights
(3) n/c
If P801 or P802 is unplugged, LD701 blinks at a rate of 3 times 3 P-DIM 42.29V Total Voltage Drop (Bright, Vivid)
every 5 seconds. 2 (2) 3.28V 144 Total LEDs 6 Blocks
DRV-ON
24 LEDs per-Block 3.26V per-diode Voltage drop
(1) 3.51V P_DIM (1.58V (50%) Backlight Power 79.7V. Backlight Drive
1 PWR-ON
16.16V.
BL On Note: Sometimes LD701 blinks during normal start-up (7 times).
Local Dimming Error Code.

September 2016 Page 02 LG

LG
2015 Direct View UHD Training
55UF7600 WebOS 2.0 UHD LCD TV
T-CON BOARD INFORMATION

T-CON Board Layout

y and
Voltage Measurements
55UF7600 T-CON Board (Photo) 55UF7600 (2015) T-CON Board Section

September 2016 Page 01

LG
 55UF7600 T-CON (TFT Drive) Components Identified 55UF7600 (2015) T-CON Section
Caution: Make sure the screws are installed when the T-CON is operating, damage may occur without them.
Note: To run the Panel Test (Testing the T-CON without the CN5 “T-CON” to P201 "SMPS"
Main board), simply unplug CN1. Jump 12V to the fuse F1. TO MAIN CN1 PIN LABEL RUN Diode Check
Apply power to the set. (Backlights and Power Supply should be Warning Do Not Use Jig VIN: (PANEL_VCC 12V) 1 V_SYNC 0.03V 0.76V
working OK). T-CON outputs color patterns on the screen. This Pins 1-2 (Gnd) 2 Gnd Gnd Gnd
test confirms the T-CON, Power Supply, Panel and Backlights LVDS Pins 3-5 (11.97V)
3 SIN 0.08V 0.76V
are working normally. (Note: If backlights are not working, apply From Main
12V to fuse and use a flashlight behind the panel to look for
CN1 Panel_VCC Supply
4 SCLK 0.06V 0.86V

pattern changes).
Local Dimming
Gnd Gnd
(11.76V) to SMPS
(8.09V) (11.76V)
Warning: Do not use VIN
HVDD VIN U1
the Smart Jig on this (11.76V) CN5 Pin 1 Gnd
T-CON. Damage will VIN (3.30V) F1 Pin 2 Gnd
occur. (8.09V) VCC 5A/125V L4 Pin 3 Gnd
FL3 L1 44 1 (1.20V) FL2 Pin 4 Gnd
(16.66V) Pin 5 3.27V
L6 45 176 Vcore
Pin 6 3.26V
Q2 28 15
D1 Q2
(11.76V) D4 Pin 7 3.29V
Pin 1 Gnd
29 14
U1 Pin 8 3.30V
Pin 2 0.61V U2 (1.80V)
Pin 3 -0.27V (16.61V) D3 42 1 VGL1 UC1 VCC18
7
6 1
24
Q3 C511 16.64V VDD
Pin 4 -4.98V 43 56 C512 16.64V VDD
Pin 5 4.70V L3 (-4.97V) 12 19
VDD C513 8.09V HVDD
VGH 13 18
Pin 6 4.71V
(16.63V) (28.05V)
MCLK EQ
RS1 U4 U3 Source C510 1.80V VCC18
88 133
GCLK GST
89 132
10Mhz (16.65V) V1 15.79V
C502 16.64V VDD RS1 (1.81V) VDD V5 12.12V
CLK8
CLK6
CLK4
CLK2

C501 16.64V VDD VCOM1 1.63Vdc V9 8.39V

C511
C512
C513
C510
VCOM2
C500
C503
C501
C502

C503 8.09V HVDD

3.72V p/p V1 V9 V14 V10 7.78V
C500 1.80V VCC18 VST V5 V10 V18
Top Legs V14 3.90V
VGH_EVEN VCOMRFB
V18 0.38V
CN2 CN3
CLK7
CLK5
CLK3
CLK1

VCOM1 5.94V VGH_ODD 1.56Vdc

VCOM2 6.14V 3.58V p/p
VST -4.91V VCOMRFB 5.90V
5 10 15 20 25 30 35 40 45 50 55 60 Bottom Legs 5 10 15 20 25 30 35 40 45 50 55 60
VGH_EVEN -4.96V to 28V*
VGT_ODD -4.96V to 28V*
* Toggles Every Second
CN2 Key Voltages CN3 Key Voltages Q3
Vcore Pin 33 Vcore Pin 28 Pin 1 8.99V
CLK1 8.91V Pin 2 16.65V
CLK1 – CLK8
CLK2 8.96V VCC18 Pin 34, 35 VCC18 Pin 26, 27 Pin 3 16.66V
32.8V - 33.0V p/p GCLK MCLK GST
CLK3 8.96V HVDD Pin 36 3.56V p/p 3.60V p/p 3.24V p/p HVDD Pin 25
CLK4 8.96V U4
CLK5 8.91V VDD Pin 37-40 VDD Pin 21-24
Pin 1 Gnd
CLK6 8.91V Pin 2 1.81V
CLK7 8.91V VGL1 Pin 45 VGL1 Pin 16
All have similar Pin 3 3.30V
CLK8 8.91V VGH_EVEN Pin 49 VGH_EVEN Pin 12
waveforms
EQ
VGH_ODD Pin 50 No Waveform VGH_ODD Pin 11
VGH Pin 51 VGH Pin 10
CN2 Video: Pins 14, 15 / 17, 18 / 20, 21 / 23, 24 / 26, 27 / 29, 30 CN3 Video: Pins 31, 32 / 34, 35 / 37, 38 / 40, 41 / 43, 44 / 46, 47

January 2016 Page 02 LG