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
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