LG UltraGear 27GL850 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
P/NO : MFL70211519 (1906-REV00)
LED MONITOR
SERVICE MANUAL
LM61C
27GL850 27GL850-BB
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.

- 2 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
CONTENTS .............................................................................................. 2
SAFETY PRECAUTIONS ........................................................................ 3
SPECIFICATION....................................................................................... 4
ADJUSTMENT INSTRUCTION ................................................................ 6
BLOCK DIAGRAM ................................................................................... 7
EXPLODED VIEW .................................................................................... 8
DISASSEMBLY ........................................................................................ 9
TROUBLE SHOOTING GUIDE .............................................................. 11
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

- 4 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
SPECIFICATION
No Remark
1
2
3
4
5
General
Scope
Item Content
Customer BRAND
UserModelName 27GL850
Saleregion Worldwide
Feature 27”LCD
MONITOR(gaming)
ChassisName
G M d R ti SES
6
ExternalSW
&Adj. 5-wayjoystickswitch
Powercordcan
bechanged
Accordingto
region.
Function
G
ame
M
o
d
e,
R
atio,
S
.
E
.
S
,
OnScreenControl,
Gammacalibration
7 PowerCord
Length:1.55±0.05M/
Shape:Wall-out/Color
:Black
Weight:0.16kg±10%
6
HDMI
Length:1.5m±0.05m
Shape : Detachable Type
/Color:Black EAD63954401
8 Cable
CONNECTOR : 100 Ω ±
None
DisplayPor
t
Length:1.5m±0.05m
Shape : Detachable Type
/ Color : Black / Weight :
0.095kg±10% EAD63749401
CABLE:100Ω±5Ω
P/N:
EAY62990913
9 Power
Input: AC90~264V
47~63Hz
Output: DC 19V 3.42A,
65W Ad t
10 SETaccessory/
RefertoBOM
P/No Specification
KRSuffix:
LM270WQA-
SSA1-8B9
EAJ6538
7901
LM270WQA
-SSA1
P/N:
EAJ65488701
EAY
629909
1
3
Factorycalibrationreport 0.002kg
11 Applyingmodulelist
9
Power
6
5WA
d
apte
r
Color:Black,Weight:
0.6kg±5%

- 5 - Copyright © LG Electronics Inc. All rights reserved.
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.
©
Back
Porch(B)
Resolution
(HDMI/DP)
H(Pixels) + 31.469 800 640 16 96 48
V(Lines) - 59.94 525 480 10 2 33
H(Pixels) - 37.5 840 640 16 64 120
V(Lines) - 75 500 480 1 3 16
H(Pixels) + 46.875 1056 800 16 80 160
V(Lines) + 75 625 600 1 3 21
H(Pixels)
+
37 879
1056
800
40
128
88
640x480(HDMI/DP)1 48.75
2 31.5 640x480(HDMI/DP)
3 49.5 800x600(HDMI/DP)
H(Pi
xe
l
s
)
+
37
.
879
1056
800
40
128
88
V(Lines) + 60.317 628 600 1 4 23
H(Pixels) - 48.363 1344 1024 24 136 160
V(Lines) - 60 806 768 3 6 29
H(Pixels) + 60.023 1312 1024 16 96 176
V(Lines) + 75.029 800 768 1 3 28
H(Pixels) + 54.347 1472 1152 32 96 192
V(Lines) + 60.05 905 864 1 3 37
4 40 800x600(HDMI/DP)
5 65 1024x768(HDMI/DP)
6 78.75 1024x768(HDMI/DP)
7 79.99 1152x864(HDMI/DP)
H(Pixels) - 49.702 1680 1280 72 128 200
V(Lines) + 59.81 831 800 3 6 22
H(Pixels) + 63.194 1440 1280 48 32 80
V(Lines) - 59.96 1054 1024 3 7 20
H(Pixels) + 79.976 1688 1280 16 144 248
V(Lines) + 75.025 1066 1024 1 3 38
H(Pixels) + 45 1650 1280 110 40 220
V(Li )
60
750
720
5
5
20
8 83.5 1280x800(HDMI/DP)
9 91 1280x1024(HDMI/DP)
10 135 1280x1024(HDMI/DP)
11 74.25 1280x720(HDMI/DP)
V
(
Lines
)
+
60
75
0
7
20
55
20
H(Pixels) + 60 1800 1600 24 80 96
V(Lines) + 60 1000 900 1 3 96
H(Pixels) + 64.674 1840 1680 48 32 80
V(Lines) - 59.883 1080 1050 3 6 21
H(Pixels) + 67.5 2200 1920 88 44 148
V(Lines) + 60 1125 1080 4 5 36
H(Pixels) + 84.36 2200 1920 88 44 148
V(Lines) + 74.99 1125 1080 4 5 36
H(Pixels)
+
88.79
2720
2560
48
32
80
12 108 1600x900(HDMI/DP)
13 119 1680x1050(HDMI/DP)
14 148.5 1920x1080(HDMI/DP)
15 185.6 1920x1080(HDMI/DP)
16
241 5
2560 1440 (HDMI/DP)
H(Pixels)
+
88
.
79
2720
2560
48
32
80
V(Lines) - 59.95 1481 1440 3 5 33
H(Pixels) + 111.86 2800 2560 48 32 160
V(Lines) - 74.97 1500 1440 3 5 52
H(Pixels) + 150.92 2720 2560 48 32 80
V(Lines) - 99.95 1510 1440 3 5 62
H(Pixels) + 183 2720 2560 48 32 80
V(Lines) - 120 1525 1440 3 5 77
2560x1440(HDMI/DP)
*HDMI:OnlysupportwithAdaptivesyncOff
2560x1440(HDMI)
*HDMI:OnlysupportwithAdaptivesyncOn
2560x1440(HDMI/DP)
*HDMIpreferredtiming
18 410.5
16 241.5 2560x1440(HDMI/DP)
17 304.25
19 497.75
H(Pixels) + 222.19 2640 2560 8 32 40
V(Lines) - 144 1543 1440 3 10 90
2560x1440(HDMI/DP)
*DP:Preferredtiming
*HDMI:OnlysupportwithAdaptivesyncOff
20 586.58

- 6 - 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 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
900
920
930
300 200
500 510
910
400
330
540

- 8- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
DISASSEMBLY
1. Preparation
1.1. Preparation tool (jig)
2. Stand Assembly Separation
1) Place the monitor’s screen face down on a soft plane.
2) Release the screw and disassemble the base
3) Release the screw and disassemble the base
3. Back cover Assembly
.wercsae4elbmessasiD)4
Use hand disassemble bottom side of cabinet
then disassemble the back cover
5&6)

- 9- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
7) Remove screws and detach the latches and lines.
8）Disassemble the cabinet.

- 10 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
TROUBLE SHOOTING GUIDE
1. No Power
Replace X100
N
Check C701
Voltage Level (19V) Check Power connector
OK? Replace Adapter
Y
N Y
Check IC703 Output
Voltage Level (3.3V) Replace IC703 &
Recheck
Y
N
Check X100 Clock
27MHz
Check IC701, 702 Output
Voltage Level (5V) Replace IC701, 702 & Recheck
N
Y
Replace IC107 Flash
Memory
Y
Y
Check IC705 Output
Voltage Level (2.5V, 1.2V) Replace IC705 & Recheck
N

- 11 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
2. No Screen on
Replace FFCable
N
Module Back Light On?
Check IC601, IC602
Replace LED Driver IC
Y
N
N
Check Panel Power 10V (L700)
Check IC700 Output 10V Replace IC700 &
Recheck
Y
N
Check Panel eDP AUX
P300 (#9, 10, 36, 37) Check IC300, IC303
Repair Main B/D
Y
N
Check FFC Cable for Damage or
Open Conductors
Check LED Driver Output
(P601, P602 -1, 2, 5, 6)
Replace T-Con Board or Module
Y
Check P201 (PIN No.69)
Replace G-SYNC Module
N
Check WLED_ENABLE High?
(IC601,IC602 27pin)
Y
Replace G-SYNC Module
N

- 12 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
3. No Video – HDMI
Replace the G-SYNC Module
Check input signal format
Is it supported?
Check JK102 for proper
connection or Damage Replace the Connector
N
Y
Check HDMI Cable for Damage or
Open Connector
Y
Check I2C Signal
(EDID) Replace the IC100
N
Y
Check IC102 AUX Signal
(#J1,H1) Replace the IC102
N
Y
Check IC103 AUX Signal
(#3,4) Replace the IC103
N
Y
Y

- 13 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
4. No Video – DP
Replace the G-SYNC Module
Check input signal format
Is it supported?
Check JK101 for proper
connection or Damage Replace the Connector
N
Y
Check DP Cable for Damage or
Open Connector
Y
Check IC101 AUX Signal
(#29,30) Replace the IC101
N
Y
Y
Check IC103 AUX Signal
(#3,4) Replace the IC103
N
Y

LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION1/11
Revision:1
LG electronics






LM61C
AdjustSpecification





27GL850












HomeEntertainmentCompany
Monitor/PCBD/MonitorDev.Lab.
LGELECTRONICSINC.



LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION2/11
Revision:1
LG electronics

RevisionHistory
No.DateRevisedbyCause&ListRemark
12019‐03‐29BJkangEstablished
22019-04-03 BJkang 
32019‐05‐07LijiweiAddmoduleselection
42019‐05‐07LijiweiChangecoolcoloryvalue
52019‐05‐07BJkangChangeluminancevalue
62019‐05‐08BJkangChangewhitebalance‐>gammmaadjust
   
   
   
   
   
   
   
   
   
  
   
   

Note)RefertoECOaboutdetailofrevisionhistory.









LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION3/11
Revision:1
LG electronics
CONTENTS






1.Application
2.Designation
3.MainPCBcheckprocess
4.TotalAssemblylineprocess
5.Shippingcondition
6.Signalcompositionforadjustment

LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION4/11
Revision:1
LG electronics
1.Application
1.1ThisdocumentisappliedtoLM61Cchassis27GL850LCDMonitorwhichismanufacturedinMonitorFactoryorisproducedon
thebasisofthisdata.
1.2ManufacturingType:SET
1.3Panelname:LM270WQA‐SSA1

2.Designation
2.1Theadjustmentisaccordingtotheorderwhichisdesignatedandwhichmustbefollowed,accordingtotheplanwhichcan
bechangedonlyonagreeing.
2.2.PowerAdjustment:FreeVoltage
2.3.MagneticFieldCondition:Nil.
2.4.InputsignalUnit:ProductSpecificationStandard
2.5.Reserveafteroperation:Above5Minutes(HeatRun)
Temperature:at25℃±5°C/Relativehumidity:65±10%/Inputvoltage:100~240V,50/60Hz
2.6.Adjustmentequipments:ColorAnalyzer(CA‐210orCA‐110,UA‐10),DDCAdjustmentJigequipment,

3.MainPCBcheckprocess
*APC‐AfterManual‐Insult,executingAPC

3.1ADCProcess
‐GL850doesn’tneedADCprocessbecauseithasonlydigitalinputlikeDisplayPort,HDMI.

3.2MainPCBFunctiontest
‐Checkdisplay/audioaccordingtointerface

3.3‐1WriteHDCP1.4Key
‐.HDCP1.4KEY
a.HDCP1.4KEYisincludedinScaler.Don’tneedwriteHDCP1.4key







LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION5/11
Revision:1
LG electronics

4.TotalAssemblylineprocess
4.1EDIDSerialNumberWrite
‐ThismodelDON’TneedtowritefullediddataforupdatetheSerialnumber.
JustwritetheS/Ndatabyusingadjustmentcommand.
Send Serial data Send 24 byte
( EDID SN(4byte) + date (2byte) + Ascii SN(18byte) )
Read C/s of Serial data Read checksum data of 24 byte

4.2VerifyHDCPKey
CheckOSDwithagingonmodeorusingMasterSignalgeneratorwithHDCPOnandconnecttomonitorwithHDMI

4.3SetAutomaticStandbytime
a.SetAutomaticStandbytimebyadjustmentjigequipment:Europe:4H,Others:OFF
Commandset:F70001(forEurope–set4h)
  F70000(forothers–set0ff)
b.ChecktheAutomaticStandbytimesettingvaluebyadjustmentjigequipment.
Pleasecheckthevalueof0xA60xEEaddress
  Value:0x00‐OFF
0x04‐Set4H
4.4 Gamma adjustment
Adjust PRESET Warm(6500K) Color coordinates.
Set the CA-210 for calibration.
Set the internal White Pattern by commanding WHITEBALANCE_START Command code.
Set as Warm(6500K) by commanding COLOR_MODE_CHANGE Command code.
Gamma 2.2 calibration and verify.
Warm(6500K) color adjustment
Adjust to meet x/y color coordinate as below.
2~4 min 4~8min 8~10min 10~25min 25~40min 40min~
x 0.315 0.315 0.315 0.314 0.314 0.313
y 0.331 0.331 0.331 0.330 0.330 0.329
Save Warm(6500K) Color by commanding COLOR SAVE Command code. (tolerance ±0.010)
Insert HDMI Jack which is connected with PC for White Balance or equivalent device.
ÎTotal Assembly line should check whether the color coordinate(x,y) data refer to below table were meet or not.

LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION6/11
Revision:1
LG electronics
Color
Temperature
Cool 9,300k °K X=0.283 (±0.015)
Y=0.297 (±0.015)
<Test Signal>
Inner pattern
(255gray,100IRE)
Medium 7,500k °K X=0.299 (±0.015)
Y=0.315 (±0.015)
Warm 6,500k °K X=0.313 (±0.015)
Y=0.329 (±0.015)
Luminance
(cd/㎡)
Cool Min : 200
<Test Signal>
Inner pattern
(255gray,100IRE)
Medium Min : 220
Warm Min : 280
*Note : x,y coordinates are drifted about 0.007 after 30 mins heat-run. So checking color coordinate within 5-min at total
assembly line, consider x,y coordinates might be up to 0.007 than x,y target of each color temperature. ..
*Note : Manual W/B process
1) Power off => Power on( ‘Å’ 3 times, ‘Æ’ 1 time and push ‘◎’)
2) and push the “Å” or “Æ”.
3) In Service Menu.
※When doing Adjustment, Please make circumstance as below.
4.3DPMOperationcheck
■MeasurementCondition:100~240V@50/60Hz
1)SetInputtoDisplayPort,HDMI1,HDMI2
2)Turnoffthesourcedevice.
3)CheckDPMoperationrefertothebelowtable.

OperatingCondition
Sync(H/V)
orVideo
EUT
(MSPG6100)
LED(SET)Wattage(W)

SleepmodeOff/OffOffOff0.5W
Offmode‐‐Off0.3WDCSwitchOff

5.Shippingcondition
ÆMakesuretodoFACTORYRESETatthefinalprocess.

LGELECTRONICSINC./MONITORDIVISION
Establish:2019/03/29LM61CADJUSTMENTSPECIFICATION7/11
Revision:1
LG electronics
No.ItemContent&OutgoingCondition비고
AccessoryRefertoBOM/AndGeneral
specification(3page)
Fullaccessorylistis
includedingeneral
specification

2
Outgoing
Condition
Game
Mode
Gamer1
Game
Adjust
1msMotionBlur
ReductionOff
Adaptive‐SyncOn 
BlackStabilizer50 
ResponseTimeFast 
CrossHairOff 
GameResetNo 
Picture
Adjust
Brightness100 
Contrast70 
Sharpness50 
GammaMode2
ColorTempCustom 
R/G/B50/50/50 
BlackLevel
Dependingoninputsignal
High(RGBformat)
Low(YUVformat)

DFCOff 
PictureResetNo 
InputInputListHDMI1 
AspectRatioFullWide 
General
LanguageDependonthesaleregion 
SMARTENERGY
SAVINGLow
PowerLEDOff 
AutomaticStandby Off(EU/EK/PD/EW/MA,4H) 
HDMICompatibility
ModeOff 
DisplayPort1.4Enable Dependonsignal
OSDLockOff 
Information
SerialNumber,
TotalPowerOnTime
Resolution

ResetNo 

6.Signalcompositionforadjustment

6.1I2C(100KBPS)