55LM5800, 55LM5850 (CHASSIS:LA21B) — LG TV Service Manual (repair manual)

Model
55LM5800 55LM5850 (CHASSIS:LA21B)
Pages
44
Size
5.31 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD
File
55lm5800-55lm5850-chassis-la21b.pdf
Date

View LG 55LM5800 / 55LM5850 (CHASSIS:LA21B) Service Manual online

P/NO : MFL67402818 (1203-REV01)
CHASSIS : LA21B
MODEL : 55LM5800   
55LM5800-UC
MODEL : 
55LM5850   
55LM5850-UF
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
LED LCD TV
SERVICE MANUAL
- 2 -
CONTENTS
CONTENTS  .............................................................................................. 2
PRODUCT SAFETY  ................................................................................. 3
SPECIFICATION ....................................................................................... 4
ADJUSTMENT INSTRUCTION ................................................................ 9
SCREW ASSEMBLY WORKING GUIDE ................................................15
TROUBLE SHOOTING ............................................................................16
BLOCK DIAGRAM .................................................................................. 24
EXPLODED VIEW  .................................................................................. 25
SCHEMATIC CIRCUIT DIAGRAM  ..............................................................
- 3 -
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by      in the 
Schematic Diagram and 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 M
Ω and 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
SAFETY PRECAUTIONS
- 4 -
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range
This spec sheet is applied LCD TV with LA21B/C chassis
2. Test condition
Each part is tested as below without special notice.
1) Temperature : 25 ºC ± 5 ºC (77 ºF ± 9 ºF), CST : 40 ºC±5 ºC
2) Relative Humidity: 65 % ± 10 %
3) Power Voltage
: Standard input voltage (AC 110-240 V~, 50/60 Hz)
* Standard Voltage of each products is marked by models.
4)  Specification  and  performance  of  each  parts  are  followed 
each  drawing  and  specification  by  part  number  in 
accordance with BOM.
5)  The receiver must be operated for about 5 minutes prior to 
the adjustment.
3. Test method
1) Performance: LGE TV test method followed 
2) Demanded other specification 
- Safety : UL, CSA, IEC specification
- EMC: FCC, ICES, IEC specification 
4. General Specification
No
                 Item
Specification
Remark
1
Receiving System
1) ATSC / NTSC-M
2
Available Channel
1) VHF : 02~13
2) UHF : 14~69
3) DTV : 02-69
4) CATV : 01~135
5) CADTV : 01~135
3
Input Voltage
1) AC 100 ~ 240V 50/60Hz
Mark : 110V, 60Hz (N.America)
4
Market
NORTH AMERICA
5
Screen Size
42/47/55 inch Wide (1920 × 1080)
FHD + 60Hz
6
Aspect Ratio
16:9
7
Tuning System
FS
8
Module
Edge LED
LC550EUE-SEF1 (T120 FHD FPR 3D)
LGD
55LM5800-UC/ 55LM5850-UF
LC470EUE-SEF1 (T120 FHD FPR 3D)
LGD
47LM5800-UC/ 47LM5850-UF
LC420EUE-SEF1 (T120 FHD FPR 3D)
LGD
42LM5800-UC/ 42LM5850-UF
9
Operating 
Environment
1) Temp   :  0 ~ 40 deg
2) Humidity :   ~ 80 %
10 Storage 
Environment
1) Temp   : -20 ~ 60 deg
2) Humidity :   ~ 85 %
- 5 -
5. Component Video Input (Y, C
b
/P
b
, C
r
/P
r
)
6. RGB (PC)
No
Resolution
H-freq(kHz)
V-freq.(Hz)
Pixel clock(MHz)
Proposed
1
720*480
15.73
60.00
13.5135
SDTV ,DVD 480I
2
720*480
15.73
59.94
13.50
SDTV ,DVD 480I
3
720*480
31.50
60.00
27.027
SDTV 480P
4
720*480
31.47
59.94
27.00
SDTV 480P
5
1280*720
45.00
60.00
74.25
HDTV 720P
6
1280*720
44.96
59.94
74.176
HDTV 720P
7
1920*1080
33.75
60.00
74.25
HDTV 1080I
8
1920*1080
33.72
59.94
74.176
HDTV 1080I
9
1920*1080
67.50
60.00
148.50
HDTV 1080P
10
1920*1080
67.432
59.94
148.352
HDTV 1080P
11
1920*1080
27.00
24.00
74.25
HDTV 1080P
12
1920*1080
26.97
23.94
74.176
HDTV 1080P
13
1920*1080
33.75
30.00
74.25
HDTV 1080P
14
1920*1080
33.71
29.97
74.176
HDTV 1080P
No
Resolution
H-freq(kHz) V-freq.(Hz)
Pixel clock(MHz)
Proposed
DDC Remark
1
640*350
31.468
70.09
25.17
EGA
X
2
720*400
31.469
70.08
28.32
DOS
O
3
640*480
31.469
59.94
25.17
VESA(VGA)
O
4
800*600
37.879
60.31
40.00
VESA(SVGA)
O
5
1024*768
48.363
60.00
65.00
VESA(XGA)
O
6
1152*864
54.348
60.053
VESA
O
7
1360*768
47.712
60.015
85.50
VESA (WXGA)
O
8
1920*1080
66.587
59.934
138.5
WUXGA
O
Full HD model Only

Download LG 55LM5800 / 55LM5850 (CHASSIS:LA21B) Service Manual (Repair Manual)

Here you can view online or download LG 55LM5800 / 55LM5850 (CHASSIS:LA21B) Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair LG 55LM5800 / 55LM5850 (CHASSIS:LA21B) LCD. Information contained in LG 55LM5800 / 55LM5850 (CHASSIS:LA21B) service manual (repair manual) typically includes:

  • Disassembly, troubleshooting, programming, maintenance, remote, adjustment, installation and setup instructions.
  • Schematics, wiring and block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Parts list (bill of materials).