LG UltraFine 24MD4KL User manual

P/NO :
CHASSIS :
MODEL :
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
SERVICE MANUAL
Copyright © 2019 LG Electronics Inc. All rights reserved. Only training and service purposes.
CONFIDENTIAL
MFL70041056 (1901-REV00)
LM8KA
24MD4KL 24MD4KL-B
UltraFine 4K MONITOR

- 2 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
CONTENTS .............................................................................................. 2
SAFETY PRECAUTIONS ........................................................................ 3
SPECIFICATION ....................................................................................... 4
SOFTWARE UPDATE............................................................................... 6
BLOCK DIAGRAM ................................................................................... 7
EXPLODED VIEW .................................................................................... 8
TROUBLE SHOOTING GUIDE ................................................................ 9
TRAINING MANUAL ................................................................ 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
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
2 User Model Name 24MD4KL
3 Sale region Worldwide
4 Feature 24” LCD MONITOR(4K)
5 Chassis Name LM8KA
6 General Scope External SW & Adj. None No Control PCB
Function Thunderbolt3, Power Delivery,
USB Audio/Speaker, Ambient Light Sensor, HDCP2.2
7 Input Thunderbolt3 Thunderbolt3 (USB-C) x 2
Dynamic PD : 85W/15W
*PD ; Power delivery
USB USB3.0 / 2.0 communication
USB down USB3.0 Downstream x 3
Audio USB data format Audio
ALS Ambient Light Sensor
8 Power Code Length : 1.80 ± 0.05 m
Weight : 0.17 kg ± 10 %
Color: Black
Refer to Sufx standard
and power cord table
9 Cable Thunderbolt Length : 2.0 ± 0.05 m
Weight : 0.6 kg ± 10 %
Color: Black
Impedance 1) CABLE : 90 Ω ± 5 Ω
2) CONNECTOR : 90 Ω ± 10 Ω
10 Power Input: 100 - 240 V~ 50/ 60 Hz 2.5 A Max
Output: 19 - 21 V, 9 A
Weight : 0.67 kg ± 10 %
11 Power Rating 100-240V~ 50/60Hz 2.3A It was checked by HQ
Standard.
12 Accessory Box Thunderbolt3 Cable/USB-C Cable/Power Cord/ESG/
VESA Bracket

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Only training and service purposes.
2. Signal Timing (Resolution)
2.1. Signal (Video & Sync)
2.1.1. H/V Timing
No. Section Pol. Dot Clock
[MHz]
Frequen-
cy
[kHz]/[Hz]
Total
Cycle
(E)
Dis-
play
(A)
Front
Porch(B)
Sync.
(D)
Back
Porch(F)
Resolution
1 H(Pixels) - 25.175 31.469 800 640 16 96 48 640 x 480
V(Lines) - 59.94 525 480 10 2 33
2 H(Pixels) + 133.32 66.66 2000 1920 8 32 40 1920 x 1080
V(Lines) - 60 1111 1080 1 8 22
3 H(Pixels) + 234.59 88.86 2640 2560 8 32 40 2560 x 1440
V(Lines) - 60 1481 1440 1 8 23
4 H(Pixels) + 401.24 116.64 3440 3360 8 32 40 3360 x 1890
V(Lines) - 60 1944 1890 1 8 45
5 H(Pixels) + 257.66 65.73 3920 3840 8 32 40 3840 x 2160
V(Lines) - 30 2191 2160 1 8 22
6 H(Pixels) + 266.62 65.688 4000 3840 48 32 80 3840 x 2160
V(Lines) - 30 2222 2160 3 5 54
7 H(Pixels) + 444.36 110.5 4000 3840 48 32 80 3840 x 2160
V(Lines) - 50 2222 2160 3 5 54
8 H(Pixels) + 533.28 133.31 4000 3840 48 32 80 3840 x 2160 (1)
V(Lines) - 60 2222 2160 3 5 54
* (1) : Preferred timing.

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Only training and service purposes.
1. LG Screen Manager
Mac applications that support FW updates on monitors
24MD4KL/27MD5KL (Mac support)
1.1. FW Update
- Supports FW updates for Scala, Audio, NXP, and Hub
(24MD4KL)
- Supports FW updates for Scala, CAM, Audio, NXP, and
Hub(27MD5KL)
- Support for automatic FW updates through Internet servers
- Manual FW update support using le open
- Enables recovery in case of FW update failure
1.2. Setting
- Automatic installation when boot the Macbook.
- Automatic Updates On/Off
- Factory Reset
- Help
2. How to FW Update
1) Go to the Monitor Update tab
2) Select FW Image ZIP le for update pop-up
3) FW update started (in progress)
4) FW update completed. Cable reconnect notication mes-
sage output.
SOFTWARE UPDATE

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Only training and service purposes.
BLOCK DIAGRAM
Panel : 3840x2160
FW Update/BL Control
L R
Backlight
2-bar(4ch x 2)
USB-C Hub
(IC200)
Down1
Down2
Down3
Down4
USB2.0 Hub
(IC206)
Upstream
Flash
8Mb
Upstream
Down1
Down2
Down3
Down4
Micom
(IC300)
USB Audio
Processor
(IC301)
Flash
8Mb
Audio
Amplifier
(IC303)
Main SoC
(IC500)
LED Driver x 2EA
Flash
8Mb
Fan
70x70,1500
Thermal
Sensor
ALS
TCON LGD
23.8” eDP
I2C
PWM
USB2.0
DDC
I2C
I2C
I2C
PWM
eDP
I2C
I2S
VBUS
VBUS
USB2.0
PD
Controller
(TI) (IC100)
TBT IC
(IC600)
PD
Controller
(TI) (IC101)
TBT A_CC1/2 USB2_A
TBT B_CC1/2 USB2_B
TBT (40Gbps)
TBT (40Gbps)
UART RX / TX
DP Out
TBT B TBT A
USB3 GEN1
USB 2.0
Mux Block
USB2_PA
USB2_PB USB2_TR_A
USB2_TR_B
Flash
8Mb
4K, 3840x2160@60
I2C
I2C
I2C
I2C
I2C
EEPROM
32Kb
EEPROM
2Kb
VBUS
I2C
Main Board Sub Board

Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
EXPLODED VIEW
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts
are identified by in 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
HR2
HP1
900
540
LV1
130
120
580
HM1
300 200
400
830
AM1 700
545
590
HR3
530

- 9 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
TROUBLE SHOOTING GUIDE
1. No Power
Changethe X500
N
Ch eck
C950 Voltage: 20V
Check the Power
Co n nection
Changethe PSU
(P ower Board)
Y
N Y
Ch eck
IC903 Voltage: 3.3V
Changethe IC902
Y
N
Check X500 Clock
14.318MHz
Ch eck
IC904 Voltage: 1.1V
Change the IC903
N
Y
Change the Flash IC501
Y
Ch eck
IC901 Voltage: 1.8V
Changethe IC904
N
Y

- 10 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
2. No Display
Change the FFC Cable
N
Check the Panel Backlight
Change th e LED Sub Board
Y
N
N
Check the Voltage L903 : 10V Change the IC900
Y
N
Check the e DP Aux signal of Panel
P501(#17,18)
Ch eck th e Solder s tatus o f IC500
And change the Main Board
Y
N
Check the FFC Cable
Check the Output of LED Driver
(P901 #1~#5)
Change the Panel or T-Con board
Y
Change IC501
N
Ch eck th e Signal “W LED_E NABLE”
is High
Y

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Only training and service purposes.
3. TBT Up No Display
Change the IC500
Check the s etting of
resolution and Vertical
Frequency.
Check the Cable connection
of JK1000 /JK1001
Connect the Cable to
JK1000/JK1001
Y
N
Y
Check the TBT Cable
co nnection and damage of
Cable.
Y

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Only training and service purposes.
4. Display Color changed to Gray
Check the Foreign material of
internal FAN.
Y
Remove the Foreign material
Check the Display 10min
(Color changed to Gray)
Change the FAN
N
Change the Main PCBA
Or Change the Temperature
Sensor
Y

TRAINING MANUAL
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Purpose Applied model
Contents and Guidance
[CIC Guide] How to adjust the Audio Output and Brightness
How to adjust the Audio Output and Brightness 24MD4KL/27MD5KL
[Guidance]
1. Symptom : can’t adjust the Audio Output and Brightness in Monitor OSD.
2. CIC Guidance
1) Check PC Spec: MacBook or Windows PC
2) Customer Guide : Please guide the method according to PC as below..
24MD4KL/27MD5KL
Brightness
Audio output
Apple Logo -> System Preferences
Display adjust Brightness in the Monitor
* PC Brightness can be adjusted with PC setting
Sound Select LG UltraFine
Display Audio and can adjust
Output Volume in bottom side
Select the Speaker Icon in Windows Tray,
and then select LG UltraFine Display Audio
for adjusting the Volume
impossible.
Mac
Windows
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Purpose Applied model
Contents and Guidance.
[CIC Guide] Compatibility issue with TBT 2 to 3 Adapter.
To Guide the compatibility issue with TBT 2 to 3 Adapter. 24MD4KL/27MD5KL
[Guidance]
1. Symptom : it can be occurred the compatibility issue such as No display or No sound etc. with TBT 2 to 3 Adapter.
2. Root-Cause : Apple Device or Adapter Limitation
3. Guidance
1) Checking the symptom: To guide the customer that they need to check the Apple Device List in Apple website. And it may caused
by TBT2 to 3 Adapter or Apple Devieces.
24MD4KL/27MD5KL
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Purpose Applied model
Contents and Guidance
[CIC Guide] About USB Unrecognized
Check the customer's PC environment and inform user guide regarding not
recognizing USB devices (or USB HUB). 24MD4KL/27MD5KL
[Guidance]
1. Symptom : Unrecognized problem when connecting a USB device (or USB HUB) to a monitor.
2. Root-Cause : Compatibility Issues with PCs
3. Guidance
1) Checking the symptom : Check the manufacturer/model name of the PC used by the customer (If Mac or Windows or etc.)
2) Customer Guide : Inform customer sequentially of the following.
a) Reminding that the SF model is a Mac-only monitor, you need to ask if customer is using a Windows PC.
b) Especially for Windows PCs with Razor Blade RZ09 2015 PCs, we recommend connecting the USB device to PC
because It is a PC problem. (It is already verified)
c) For Windows PCs, You can check Thunderbolt Version in the following order.
#Reference : For Razor Blade RZ09 2015 PCs, NVM version is14 and for Razor Blade PC 2018, NVM version is 33.
Because the 2015 PC has a low NVM version, it may cause compatibility problems with monitors.
24MD4KL/27MD5KL
From the desktop icon tray,
Right-click above ICON and select "Settings" Bottom left, select “information”
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Purpose Applied model
Contents and Guidance
[CIC Guide] About USB Unrecognized
To guide customers how to use the USB device exactly (or USB HUB)
regarding not recognizing USB devices. 24MD4KL/27MD5KL
[Guidance]
1. Symptom : Unrecognized problem when connecting a USB device (or USB HUB) to the Thunderbolt input port on the monitor.
2. Root-Cause : Problem caused by lack of understanding of connection ports
3. Guidance
1) Checking the symptom : If USB unrecognized problems occur, check the following.
a) Check which port the USB device (or USB HUB) is connected to.
2) Customer Guide : Port configuration can be divided into Host input port and USB expansion port,
the USB device (or USB HUB) must be connected to the USB expansion port for normal operation.
24MD4KL/27MD5KL
Thunderbolt input port
USB expansion port
<24MD4KL>
Thunderbolt input port
USB expansion port
<27MD5KL>
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Purpose Applied model
Contents and Guidance
[CIC Guide] Recommendation guide when using Daisy Chain
Guide recommendations when using Daisy Chain with the Thunderbolt input port 24MD4KL
[Guidance]
1. Symptom : When using Daisy Chain with the Thunderbolt input port, abnormal operation may occur if it is not used as
recommended.
(No screen or Blinking screen)
2. Root-Cause : Daisy Chain Spec Limitation.
3. Guidance
1) Checking the symptom : Ask the customer if they used Daisy Chain, check the 2nd monitor model name and cable type.
2) Customer Guide :
a) Recommend to use the enclosed Thunderbolt cable when using the Daisy Chain.
b) 2nd monitor in Daisy Chain is recommended to use the 24MD4KL model whenever possible.(Guide that problems may occur
when using other models)
24MD4KL
Thunderbolt input port
USB expansion port
1stMonitor (24MD4KL)
Thunderbolt input port
USB expansion port
2nd Monitor (24MD4KL)
PC (Mac Device Recommended)
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

Purpose Applied model
Contents and Guidance
[CIC Guide] Guide on problems with using 2 PCs for 2 Thunderbolt input ports
Guide problems when it comes to using 2 PCs for 2 Thunderbolt input ports 24MD4KL
[Guidance]
1. Symptom : No screen or Charging capacity changed.
2. Root-Cause : Compatibility issues due to monitor concept.
3. Guidance
1) Checking the symptom : Ask to customer if they use 2 PCs at the same time,
and check if the screen does not display or charge after rebooting the PC.
2) Customer Guide :
a) Problem can be occur if you connect a PC to each of the Thunderbolt input ports as shown below.
b) The reason why there are the two Thunderbolt input ports is for the Daisy Chain function.
24MD4KL
썬더볼트 입력 Port
USB expansion port
24MD4KL
PC #1
PC #2
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.

24MD4KL Disassembly process
Tool Description
Tool Size (if applicable)
Screw driver
Plastic stick Jig
* Tool
* Disassemble Process
①Place Set on the table. ②Remove the stand by operating the stand release button.
Copyright ⓒ2019 LG Electronics Inc. All rights reserved.
Only training and service purposes.