LG UltraFine 27MD5KL User manual

P/NO : MFL70041064 (1904-REV00)
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
Any reproduction, duplication, distribution (including by way of email, facsimile or other electronic means),
publication, modification, copying or transmission of this Service Manual is STRICTLY PROHIBITED unless you
have obtained the prior written consent of the LG Electronics entity from which you received this Service Manual.
The material covered by this prohibition includes, without limitation, any text, graphics or logos in this Service
Manual.
LM8JA
27MD5KL 27MD5KL-BJ
27MD5KL 27MD5KL-BK
27MD5KLB 27MD5KLB-BK
UltraFine 5K 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

- 4 - Copyright © LG Electronics Inc. All rights reserved.
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 27MD5KL/27MD5KLB
3 Sale region Worldwide
4 Feature 27” LCD MONITOR(5K)
5 Chassis Name LM8JA PCB, Product spec.,
Adjustment
spec.
6 General Scope External SW & Adj. None No Control PCB
Function Thunderbolt3, Power Delivery, USB Audio/Speaker/Mic/
Webcam, Ambient Light Sensor, HDCP2.2
7 Input Thunderbolt3 Thunderbolt3 / USB-C input / PD : 94W *PD ; Power delivery
PD Prole :
5V/9V/15V/20V
USB USB3.0 / 2.0 communication
USB down USB3.0 Downstream x 3
Audio USB data format Audio
Camera Full HD Web Camera Module
Microphone 1xDigital MEMS Mic
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
Type-C Length : 1.5 m ± 0.05 m
Weight : 0.064 kg ± 10 %
Color: Black
Impedance 1) CABLE : 100 Ω ± 5 Ω
2) CONNECTOR : 100 Ω ± 10 Ω
10 Power (Adapter / PSU /LPB) 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 2.5A 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) + 522.61 133.32 3920 3840 8 32 40 3840 x 2160
V(Lines) - 60 2222 2160 1 8 53
3 H(Pixels) + 364.47 111.12 3280 3200 8 32 40 3200 x 1800
V(Lines) - 60 1852 1800 1 8 43
4 H(Pixels) + 234.59 88.86 2640 2560 8 32 40 2560 x 1440
V(Lines) - 60 1481 1440 1 8 32
5 H(Pixels) + 966.74 177.71 5280 5120 16 64 240 5120 x 2880 (1)
V(Lines) - 60 2962 2880 1 8 73
* (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

- 7 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
BLOCK DIAGRAM

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
900
HR9
HR8
HP1
120
130
540
580
HR6
LV1
HR7 590
300
200
400
150
530
591 830
140
700 AM1

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Only training and service purposes.
TROUBLE SHOOTING GUIDE
1. No Power
Changethe X500
N
Ch eck
C1102 Voltage: 20V
Check the Power
Co n nection
Changethe PSU
(P ower Board)
Y
N Y
Ch eck
IC1101 Voltage: 3.3V
Changethe IC1103
Y
N
Check X500 Clock
14.318MHz
Ch eck
IC1102 Voltage: 1.1V
Ch ange th e IC1101
N
Y
Change the Flash IC501
Y
Ch eck
IC1103 Voltage: 1.5V
Changethe IC1102
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 the IC800
Y
N
N
Check the Voltage L1107 : 10V Ch ange th e IC1100
Y
N
Check the e DP Aux signal of Panel
P502(#36,37)
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
(P800 #3)
Change the Panel or T-Con board
Y
Change IC501
N
Ch eck th e Signal “L ED_ENABLE” is
High
Y

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Only training and service purposes.
3. TBT Up No Display
Change the IC500
Check the setting of
resolution and Vertical
Frequency.
Check the Cable connection
of JK100 Connect the Cable to JK100
Y
N
Y
Check the TBT Cable
co nnection and damage o f
Cable.
Y

- 12 - Copyright © LG Electronics Inc. All rights reserved.
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.