LG 34CB99-WF User manual

P/NO :
CHASSIS :
MODEL :
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
SERVICE MANUAL
Copyright © 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
CONFIDENTIAL
P/NO : MFL70041021 (1707-REV00)
LED MONITOR
SERVICE MANUAL
LM61A
34CB99 34CB99-WF
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
BLOCK DIAGRAM ................................................................................... 7
EXPLODED VIEW .................................................................................... 8
TROUBLE SHOOTING GUIDE ................................................................ 9
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
NOTE : Specications and others are subject to change without notice for improvement.
1. General Specication
Item Content Remark
1 Customer BRAND
2 User Model Name 34UC99
3 Sale region World Wide
4 Feature 34” Wide Curved LCD MONITOR(WQHD)
5 Chassis Name LM61A
6 General Scope External SW &Adj. 5-way joystick switch
Function PBP, Picture Mode Ratio, Gamma Calibration, SES, Six
Color, 5W speaker x 2, Type-C, DisplayPort, HDMI x 2, USB
hub(USB3.0 x 2), On Screen Control
7 Input HDMI1/2 IN HDMI 1 and HDMI 2
DP IN Display Port
USB Type-C Type-C
USB UP N/A
USB 1/2 USB downstream(only with Host PC)
Quick Charge(USB 1/2)
H/P Audio L/R
8 Power Code Length : 1.55±0.05M, Shape : Wall-out
Color : White, Weight : 0.17kg
Refer to Suf-
x standard and
power cord table
9 Cable USB Type-C Length : 1.0±0.05 M
Shape : Detachable Type
Color: White Pin : 24P
Weight : 0.48kg±10%,
Displayport Length : 1.5±0.05 M
Shape : Detachable Type
Color : White
Weight : 0.10kg±10%,
HDMI Length : 1.5±0.05 M
Shape : Detachable Type
Color : White
Weight : 0.09kg±10%
10 Gender USB Type-C to A Color : White Weight : 0.006kg±10%,
11 Power Input: 100-240V~ 50/60Hz 2.5A Max
Output: DC 19V 9.48A 180W Adapter
Color : White, Weight : 0.9kg±10%, without vinyl bag

- 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
No. Section Pol. Dot Clock
[MHz]
Frequency
[kHz]/[Hz]
Total
Cycle
(E)
Display
(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) + 40 37.879 1056 800 40 128 88 800 x 600
V(Lines) + 60.317 628 600 1 4 23
3 H(Pixels) - 65 48.363 1344 1024 24 136 160 1024 x 768
V(Lines) - 60 806 768 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
5 H(Pixels) + 74.25 45 1650 1280 110 40 220 1280x720
V(Lines) + 60 750 720 5 5 20
6 H(Pixels) + 108 63.981 1688 1280 48 112 248 1280x1024
V(Lines) + 60.02 1066 1024 1 3 38
7 H(Pixels) + 108 60 1800 1600 24 80 96 1600 x 900
V(Lines) + 60 1000 900 1 3 96
8 H(Pixels) - 146.25 65.29 2240 1680 104 176 280 1680x1050
V(Lines) + 59.954 1089 1050 3 6 30
9 H(Pixels) + 148.5 67.5 2200 1920 88 44 148 1920x1080
V(Lines) - 60 1125 1080 4 5 36
10 H(Pixels) - 185.58 66.7 2784 2560 64 64 96 2560x1080
V(Lines) + 60 1111 1080 3 10 18
11 H(Pixels) + 157.75 43.82 3600 3440 48 32 80 3440x1440
V(Lines) + 29.99 1461 1440 3 10 8
12 H(Pixels) + 265.25 73.68 3600 3440 48 32 80 3440x1440
V(Lines) + 49.99 1474 1440 3 10 21
13(1) H(Pixels) + 319.75 88.82 3600 3440 48 32 80 3440x1440
V(Lines) + 59.97 1481 1440 3 10 28
14 H(Pixels) + 429.8 110.77 3880 3440 144 96 200 3440x1440
V(Lines) + 75.05 1476 1440 8 4 24
* (1): Preferred timing.

- 6 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
2.3. HDMI Video input
Factory support mode Horizontal frequency Vertical frequency
(Preset Mode) (KHz) (Hz)
1 640x480P 31.47 60
2 720x480P 31.47 60
3 1280x720P 45 60
4 1920x1080P 67.5 60
5 1280x720P 37.5 50
6 1920x1080P 56.25 50
7 2560x1080P 56.25 60
8 2560x1080P 66 50
9 720x576P 31.25 50

- 7 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
BLOCK DIAGRAM
IC200 SPI
WQHD
Panel (3440 X 1440)
HDMI 1
DPRX, AUXN, HPD
HDMI 2
IC101
(Swi tch )
Key1, Key2
DDR2
SDRAM
(128MB)
LED Driver IC Flash
Memo ry
(8M)
TMDS // DDC // HPD
Joysti ck
(Control Key)
DP
System
EEPROM
(32KB)
I2C
IC100
(Swi tch )
USB Type-C
EDID
EEPROM (내장)
HP Out
L/R Out
HP AMP
USB Type A
USB Type A
USB To UART
EEPROM
MUX DP Signal
PD Controller
Control
DP, USB 3.0
USB HUB USB 3.0
USB 2.0
I2C
UART
I2C
CC통신, USB 2.0
WLED_ENABLE WLED_ADIM
Flash
Memo ry
(8M)
SPI
( HDMI 2.0 )
E-DP
DC-DC
D+/ D-
VBUS=5V
Billboard
EEPROM
(256KB)
I2C
D+/ D-
USB Typ e A / USB2.0 o nly /Service only
IC500
IS2 Switch
I2S
SPEAKER
LED Driver IC

Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
- -
EXPLODED VIEW
900
910
911
830
300
200
540
121
120
510
400
720 LV1
700
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

- 9 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
TROUBLE SHOOTING 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 Hub IC : function of HUB to the PC, should be connect to the PC USB-A/B cable.
Location No. : IC701