LG 38WN75C User manual

P/NO :
CHASSIS :
MODEL :
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
SERVICE MANUAL
Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
CONFIDENTIAL
P/NO : MFL69413822 (2004-REV00)
LED MONITOR
SERVICE MANUAL
LM61A
38WN75C 38WN75C-BK
38BN75C 38BN75C-BK

- 2 - Copyright © - LG Electronics Inc. All rights reserved.
Only training and service purposes.
CONTENTS .............................................................................................. 2
SAFETY PRECAUTIONS ........................................................................ 3
SPECIFICATION ....................................................................................... 4
TROUBLE SHOOTING GUIDE ................................................................ 7
BLOCK DIAGRAM ................................................................................... 8
EXPLODED VIEW .................................................................................... 9
DISASSEMBLY ...................................................................................... 10
DOWNLOAD ............................................................................ APPENDIX
CONTENTS

- 3 - Copyright © - LG Electronics Inc. All rights reserved.
Only training and service purposes.
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Exploded View.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance
An isolation 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 circuitry 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 1 W), keep the resistor 10 mm away from PCB.
Keep wires away from high voltage or high temperature parts.
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 position, 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 1 MΩand 5.2 MΩ.
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 1.5 K / 10 watt resistor in parallel with a 0.15 uF 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 exposed metallic part. Any voltage
measured must not exceed 0.75 volt RMS which is corresponds to
0.5 mA.
In case any measurement is out of the limits specified, 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
IMPORTANT SAFETY NOTICE
To Instrument's
exposed
METALLIC PARTS
Good Earth Ground
such as WATER PIPE,
CONDUIT etc.
AC Volt-meter
SAFETY PRECAUTIONS

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Only training and service purposes.
SPECIFICATION
NOTE : Specications and others are subject to change without notice for improvement.
1. General Specication
No Item Content Remark
1 Customer BRAND BRAND : LGE Product
2 User Model Name 38WN75C
3 Sale region Worldwide
4 Feature 38”LCD MONITOR (21:9 2300R Curved WQHD+)
5 Chassis NameLM95A PCB, Product spec., Adjustment spec.
6General
Scope
External SW & Adj. Joystick switch Up / Down / Left / Right / OK (Power) Press and Hold : Power off
Function Picture Mode, Ratio, S.E.S, Six Color,
On Screen Control,Dual Controller, Factory calibration
7 Input
HDMI IN HDMI1,2(2.0)
DP IN Display Port (1.4)
USB Up N/A
USB DN N/A Up to 5V 0.9A DC
H/P OUT Audio L/R
8
Power Cord
Length 1.55±0.05m: Refer to Suffix standard and power
cord Table.
Weight 0.17kg ± 10%,
Color Black
DisplayPort
Length
N/A
Weight
Color
Impedance
HDMI
Length 1.50m ± 0.05m
P/N : EAD65185201
(Refer to BOM)
Weight 0.09kg ± 10%
Color Black
Impedance 1)CABLE : 100Ω±5Ω
2)CONNECTOR : 100Ω±10Ω
10 Power (Adapter / PSU /LPB)
Input: 100-240V~ 50/60Hz
Output: DC 19V 3.42A 65W Adapter
Color : Black, Weight : 0.4kg±10%, without vinyl bag
P/N : EAY62990906
(Refer to BOM)
11 Power Rating 19V,3.0 Request to regulation team
12 Accessory Box - Not applied
13 Applying module list
P/No Specification 34” 21:9 Curved WQHD MODULE
(LG Display)(Refer to BOM)
EAJ63749901
LM340UW3-SSA1 WQHD 34INCH 3440X1440

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Only training and service purposes.
2. Signal Timing (Resolution)
2.1. Signal (Video & Sync)
2.2. H/V Timing
mode section polarity
DOT
CLOCK
[MHz]
Frequency
[kHz]/[Hz]
Total
Period
(E)
Display
(A)
Front
Porch
(D)
Sync.
(C)
Back
Porch(B) Resolution
1H(Pixels)
-
25.175
31.469 800 640 16 96 48
640 x 480
V(Lines)
- 59.94 525 480 10 2 33
2H(Pixels)
+
40.0
37.879 1056 800 40 128 88
800 x 600
V(Lines)
+ 60.317 628 600 1 4 23
3H(Pixels)
-
65.0
48.363 1344 1024 24 136 160
1024 x 768
V(Lines)
- 60.0 806 768 3 6 29
4H(Pixels)
+
79.99
54.347 1472 1152 32 96 192
1152 x 864
V(Lines)
+ 60.05 905 864 1 3 37
5H(Pixels)
+
74.25
45 1650 1280 110 40 220
1280 x 720
V(Lines)
+ 60 750 720 5 5 20
6H(Pixels)
-
83.5
49.702 1680 1280 72 128 200
1280 x 800
V(Lines)
+ 59.810 831 800 3 6 22
7H(Pixels)
+
108.0
63.981 1688 1280 48 112 248
1280 x 1024
V(Lines)
+ 60.021066 1024 1 3 38
8H(Pixels)
-
146.25
60.001800 1600 24 80 96
1600 x 900
V(Lines)
+ 60.001000 900 1 3 96
9H(Pixels)
+
148.50
65.292240 1680 104 176 280
1680 x 1050
V(Lines)
- 59.954 1089 1050 3 6 30
10 H(Pixels)
+
174.50
67.502200 1920 88 44 148
1920 x 1080
V(Lines)
- 60 1125 1080 4 5 36
11 H(Pixels)
+
194.75
48.688 4000 3840 48 32 80
3840 x 1600
V(Lines) -
29.998 1623 1600 3 10 10
12 H(Pixels)
+
327.50
81.875 4000 3840 48 32 80
3840 x 1600
V(Lines)
- 49.985 1638 1600 3 10 25
13
(2)
H(Pixels)
+
395.00
98.754000 3840 48 32 80
3840 x1600
V(Lines) -
59.994 1646 1600 3 10 33

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Only training and service purposes.
2.3. HDMI Video input
Factory support
mode
Horizontal
frequency
Vertical
frequency
(Preset Mode)(KHz) (Hz)
1480P 31.5 60
2720P 45 60
31080P 67.5 60
42160P 135 60

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Only training and service purposes.
TROUBLESHOOTING GUIDE
1) MAIN IC : Process display/audio signal/control signal
Location no. : IC200
2) DC-DC Converter : Convert from 19V to proper voltage according to IC spec
Location No. : IC402, IC403, IC404, IC600, IC601, IC901, IC902, IC903, IC904
3) Serial ash memory for Monitor : rmware saving
Location No. : IC202
4) LED driver IC : Supporting proper voltage and current according to BLU spec
Location No. : IC600, IC601
5) Headphone AMP : Amplify audio signal from Main IC and then provide amplifying signal to H/P interface
Location No. : IC503
6) USB-C PD Controller : Set the signal from USB-C input and communicate with Source Device.
Location No. : IC801
7) Mux IC : Separate DP and USB signal of USB-C input, controlled by PD controller.
Location No. : IC800
8) USB Hub IC : function of HUB to the PC, should be connect to the PC with USB-C/C or USB-C/A cable.
Location No. : IC701

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Only training and service purposes.
BLOCK DIAGRAM
RTD2595LT
SPI
WQHD
Panel (3840 X 1600)
HDMI 1
DPRX, AUXN, HPD
HDMI 2
Key1, Key2
LED Driver IC
MP3378E Flash
Memory
(32MBIT)
TMDS // DDC // HPD Joystick
(Control Key)
DP
System
EEPROM
HP Out
TPA6138A
WLED_ENABLE WLED_ADIM
( HDMI 2.0 )
E-DP
(DP1.2)
LED Driver IC
MP3378E

Copyright © - LG Electronics Inc. All rights reserved.
Only training and service purposes.
- -
EXPLODED VIEW
910
900
100
300
500 510
330
200 400
540
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts
are identified by in the EXPLODED VIEW.
It is essential that these special safety parts should be replaced with the same components as recommended
in this manual to prevent Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
IMPORTANT SAFETY NOTICE

- 10 - Copyright © - LG Electronics Inc. All rights reserved.
Only training and service purposes.
DISASSEMBLY
1. Preparation
1.1. Preparation tool (jig)
1.2. Preparation tool (Curved PAD)
2. Stand Assembly Separation
1) Lay the set by the Curved PAD in Box
2) Disassemble the Stand after pull the button to down
3) Disassemble the Thumb Screw
4) Remove the Screw (4ea).
5) Disassemble the Back Cover (By using JIG)

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Only training and service purposes.
6) Disconnect LED Cable , Control Assemble (Latch Type) ,
Bluetooth PCB cable, FFC cable, Speaker
7) Disconnect Control Assemble, BT PCB (Latch Type)
8) Remove the screw. (4EA)
9) Remove the screw. (18EA)

DOWNLOAD
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

1. Firmware download method
▶ISP method
Requirement SW : ISP_Tool V4.5.1.9.8.exe (Mstar)
Step1. Connect monitor and Mstar Jig of PC using HDMI or
USB cable.
Step3. Install Mstar ISP USB driver
( If USB cable connect to the PC,
USB driver is automatically installed in Windows.
If driver can not automatically update driver in PC,
please check whether internet normally operate or
the system of Windows can update. )
Step4. Check a installed driver of Mstar ISP USB in device manager.
(Installing a driver, port should be shown as “USB Serial Port”. however, port number can be different.)
Connect PC using a USB type A
And type B.
Connect HDMI cable to the HDMI1 port of
monitor
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Step5. After extracting ISP Tool V4.5.1.9.8.zip then execute ISP_Tool V4.5.1.9.8.exe
Step6. Please click “Connect” button after connecting HDMI cable to HDMI1 port of monitor.
If monitor can communicate normally ISP, the following pop-up should be shown as “Device Type is MX25L8005”.
1. Firmware download method
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Step6. After clicking “Read” button, the selected SW
file should be opened to be updated FW.
1. Firmware download method
Step7. Make sure match the checksum
Please ensure that it matches the checksum(E3AD) between
file name(E3AD).
EX :
UC99_MST9U11Q1_MSTAR_V2.07_E3AD_rev2728_160720.bin
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Step8. Move “Auto”, then Click “Run” button
1) Click “Auto” button
2) Verify setting option
( The “File Area” of erase device should be selected in order to maintain system
and factory calibration data. )
3) Click “Run” button
1. Firmware download method
3
1
2
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

2. How to update the monitor FW using USB memory storage.
[Advance Preparation]
1. Please prepare an USB memory stick. (Except for the external HDD disk)
[Note] The file system must use the following format. (NTFS, FAT, FAT32)
3. Please make a new folder like as LG_MNT of USB memory stick. (Ex. E:\LG_MNT)
4. Please copy monitor FW(UC99_MST9U11Q1_MSTAR_V3.XX_XXXX_revXXXX_16XXXX.bin) to the folder of LG_MNT.
[Note] The downloading feature does not work properly when using the download file from the company security.
4. Please remove the plastic, which is marked as ‘DO NOT USE’ on the monitor’s rear.
5. Please insert the USB memory stick to the USB 2.0 port.
Title Monitor F/W update feature supports through a SVC USB port. For Oversea( √)
Product MNT Product
Name Monitor Model
Name 38UC99 Troubleshooting () Operation (√) Installation ( )
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

2. How to update the monitor FW using USB memory storage.
Title Monitor F/W update feature supports through a SVC USB port. For Oversea( √)
Product MNT Product
Name Monitor Model
Name 38UC99 Troubleshooting () Operation (√) Installation ( )
[Description]
- Customer Condition
1. If the FW of USB must include a higher version more than version of current monitor, the updating feature will be normally worked.
3. User can choice whether or not performing a updating feature by the selection of user.
- Factory Condition (Aging On)
1. After searching the highest version in LG_MNT folder of USB, the updating feature has been automatically performed regardless of the
current version of monitor.
[Common] When the updating feature is completed, monitor will turn off/on automatically after 3 seconds.
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.

2. How to update the monitor FW using USB memory storage.
Title Monitor F/W update feature supports through a SVC USB port. For Oversea( √)
Product MNT Product
Name Monitor Model
Name 38UC99 Troubleshooting () Operation (√) Installation ( )
[Troubleshooting]
Q. The power turns off suddenly during updating FW in the status of progress bar, monitor does not work.
The power cable should be removed and reconnected after inserting an USB memory stick including FW in the determined folder.
[Note] After searching the highest version in LG_MNT folder of USB, the recovering feature has been automatically performed
After 40 seconds, the monitor will be normally recovered by itself.
Q. The power turns off suddenly during updating PD FW under 50% status of progress bar, how can I do?
After turning on the power, the updating will be progress again from the beginning percentage.
Copyright ⓒ2016 - 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.