DOWNLOAD LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) Service Manual ↓ Size: 5.03 MB | Pages: 44 in PDF or view online for FREE

Model
55LM4610 55LM4650 (CHASSIS:LB21B)
Pages
44
Size
5.03 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD
File
55lm4610-55lm4650-chassis-lb21b.pdf
Date

LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) Service Manual ▷ View online

- 4 -
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service 
manual and its supplements and addenda, read and follow the 
SAFETY PRECAUTIONS on page 3 of this publication.
NOTE: If unforeseen circumstances create conflict between the 
following servicing precautions and any of the safety precautions 
on page 3 of this publication, always follow the safety precautions. 
Remember: Safety First.
General Servicing Precautions
1.  Always unplug the receiver AC power cord from the AC power 
source before;
a.  Removing or reinstalling any component, circuit board mod-
ule or any other receiver assembly.
b.  Disconnecting or reconnecting any receiver electrical plug or 
other electrical connection.
c.  Connecting a test substitute in parallel with an electrolytic 
capacitor in the receiver.
CAUTION: A wrong part substitution or incorrect polarity 
installation of electrolytic capacitors may result in an explo-
sion hazard.
2.  Test high voltage only by measuring it with an appropriate 
high voltage meter or other voltage measuring device (DVM, 
FETVOM, etc) equipped with a suitable high voltage probe.
Do not test high voltage by "drawing an arc".
3.  Do not spray chemicals on or near this receiver or any of its 
assemblies.
4.  Unless specified otherwise in this service manual, clean 
electrical contacts only by applying the following mixture to the 
contacts with a pipe cleaner, cotton-tipped stick or comparable 
non-abrasive applicator; 10 % (by volume) Acetone and 90 % 
(by volume) isopropyl alcohol (90 % - 99 % strength)
CAUTION: This is a flammable mixture.
Unless specified otherwise in this service manual, lubrication of 
contacts in not required.
5.  Do not defeat any plug/socket B+ voltage interlocks with which 
receivers covered by this service manual might be equipped.
6.  Do not apply AC power to this instrument and/or any of its 
electrical assemblies unless all solid-state device heat sinks are 
correctly installed.
7.  Always connect the test receiver ground lead to the receiver 
chassis ground before connecting the test receiver positive 
lead.
Always remove the test receiver ground lead last.
8.  Use with this receiver only the test fixtures specified in this 
service manual.
CAUTION: Do not connect the test fixture ground strap to any 
heat sink in this receiver.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid-state) devices can be damaged eas-
ily by static electricity. Such components commonly are called 
Electrostatically Sensitive (ES) Devices. Examples of typical ES 
devices are integrated circuits and some field-effect transistors 
and semiconductor “chip” components. The following techniques 
should be used to help reduce the incidence of component dam-
age caused by static by static electricity.
1.  Immediately before handling any semiconductor component or 
semiconductor-equipped assembly, drain off any electrostatic 
charge on your body by touching a known earth ground. Alter-
natively, obtain and wear a commercially available discharging 
wrist strap device, which should be removed to prevent poten-
tial shock reasons prior to applying power to the unit under test.
2.  After removing an electrical assembly equipped with ES 
devices, place the assembly on a conductive surface such as 
aluminum foil, to prevent electrostatic charge buildup or expo-
sure of the assembly.
3.  Use only a grounded-tip soldering iron to solder or unsolder ES 
devices.
4.  Use only an anti-static type solder removal device. Some solder 
removal devices not classified as “anti-static” can generate 
electrical charges sufficient to damage ES devices.
5.  Do not use freon-propelled chemicals. These can generate 
electrical charges sufficient to damage ES devices.
6.  Do not remove a replacement ES device from its protective 
package until immediately before you are ready to install it. 
(Most replacement ES devices are packaged with leads electri-
cally shorted together by conductive foam, aluminum foil or 
comparable conductive material).
7.  Immediately before removing the protective material from the 
leads of a replacement ES device, touch the protective material 
to the chassis or circuit assembly into which the device will be 
installed.
CAUTION: Be sure no power is applied to the chassis or circuit, 
and observe all other safety precautions.
8.  Minimize bodily motions when handling unpackaged replace-
ment ES devices. (Otherwise harmless motion such as the 
brushing together of your clothes fabric or the lifting  of your 
foot from a carpeted floor can generate static electricity suf-
ficient to damage an ES device.)
General Soldering Guidelines
1.  Use a grounded-tip, low-wattage soldering iron and appropriate 
tip size and shape that will maintain tip temperature within the 
range or 500 °F to 600 °F.
2.  Use an appropriate gauge of RMA resin-core solder composed 
of 60 parts tin/40 parts lead.
3. Keep the soldering iron tip clean and well tinned.
4.  Thoroughly clean the surfaces to be soldered. Use a mall wire-
bristle (0.5 inch, or 1.25 cm) brush with a metal handle.
Do not use freon-propelled spray-on cleaners.
5.  Use the following unsoldering technique
a.  Allow the soldering iron tip to reach normal temperature. 
(500 °F to 600 °F)
b. Heat the component lead until the solder melts.
c.  Quickly draw the melted solder with an anti-static, suction-
type solder removal device or with solder braid.
CAUTION: Work quickly to avoid overheating the circuit 
board printed foil.
6.  Use the following soldering technique.
a.  Allow the soldering iron tip to reach a normal temperature 
(500 °F to 600 °F)
b.  First, hold the soldering iron tip and solder the strand against 
the component lead until the solder melts.
c.  Quickly move the soldering iron tip to the junction of the 
component lead and the printed circuit foil, and hold it there 
only until the solder flows onto and around both the compo-
nent lead and the foil.
CAUTION: Work quickly to avoid overheating the circuit 
board printed foil.
d.  Closely inspect the solder area and remove any excess or 
splashed solder with a small wire-bristle brush.
- 5 -
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through 
which the IC leads are inserted and then bent flat against the cir-
cuit foil. When holes are the slotted type, the following technique 
should be used to remove and replace the IC. When working with 
boards using the familiar round hole, use the standard technique 
as outlined in paragraphs 5 and 6 above.
Removal
1.  Desolder and straighten each IC lead in one operation by 
gently prying up on the lead with the soldering iron tip as the 
solder melts.
2.  Draw away the melted solder with an anti-static suction-type 
solder removal device (or with solder braid) before removing 
the IC.
Replacement
1.  Carefully insert the replacement IC in the circuit board.
2.  Carefully bend each IC lead against the circuit foil pad and 
solder it.
3.  Clean the soldered areas with a small wire-bristle brush.
(It is not necessary to reapply acrylic coating to the areas).
"Small-Signal" Discrete Transistor
Removal/Replacement
1.  Remove the defective transistor by clipping its leads as close 
as possible to the component body.
2.  Bend into a "U" shape the end of each of three leads remaining 
on the circuit board.
3.  Bend into a "U" shape the replacement transistor leads.
4.  Connect the replacement transistor leads to the corresponding 
leads extending from the circuit board and crimp the "U" with 
long nose pliers to insure metal to metal contact then solder 
each connection.
Power Output, Transistor Device
Removal/Replacement
1. Heat and remove all solder from around the transistor leads.
2. Remove the heat sink mounting screw (if so equipped).
3.  Carefully remove the transistor from the heat sink of the circuit 
board.
4.  Insert new transistor in the circuit board.
5.  Solder each transistor lead, and clip off excess lead.
6.  Replace heat sink.
Diode Removal/Replacement
1.  Remove defective diode by clipping its leads as close as pos-
sible to diode body.
2.  Bend the two remaining leads perpendicular y to the circuit 
board.
3.  Observing diode polarity, wrap each lead of the new diode 
around the corresponding lead on the circuit board.
4.  Securely crimp each connection and solder it.
5.  Inspect (on the circuit board copper side) the solder joints of 
the two "original" leads. If they are not shiny, reheat them and if 
necessary, apply additional solder.
Fuse and Conventional Resistor
Removal/Replacement
1.  Clip each fuse or resistor lead at top of the circuit board hollow 
stake.
2.  Securely crimp the leads of replacement component around 
notch at stake top.
3.  Solder the connections.
CAUTION: Maintain original spacing between the replaced 
component and adjacent components and the circuit board to 
prevent excessive component temperatures.
Circuit Board Foil Repair
Excessive heat applied to the copper foil of any printed circuit 
board will weaken the adhesive that bonds the foil to the circuit 
board causing the foil to separate from or "lift-off" the board. The 
following guidelines and procedures should be followed whenever 
this condition is encountered.
At IC Connections
To repair a defective copper pattern at IC connections use the 
following procedure to install a jumper wire on the copper pattern 
side of the circuit board. (Use this technique only on IC connec-
tions).
1.  Carefully remove the damaged copper pattern with a sharp 
knife. (Remove only as much copper as absolutely necessary).
2.  carefully scratch away the solder resist and acrylic coating (if 
used) from the end of the remaining copper pattern.
3.  Bend a small "U" in one end of a small gauge jumper wire and 
carefully crimp it around the IC pin. Solder the IC connection.
4.  Route the jumper wire along the path of the out-away copper 
pattern and let it overlap the previously scraped end of the 
good copper pattern. Solder the overlapped area and clip off 
any excess jumper wire.
At Other Connections
Use the following technique to repair the defective copper pattern 
at connections other than IC Pins. This technique involves the 
installation of a jumper wire on the component side of the circuit 
board.
1.  Remove the defective copper pattern with a sharp knife.
Remove at least 1/4 inch of copper, to ensure that a hazardous 
condition will not exist if the jumper wire opens.
2.  Trace along the copper pattern from both sides of the pattern 
break and locate the nearest component that is directly con-
nected to the affected copper pattern.
3.  Connect insulated 20-gauge jumper wire from the lead of the 
nearest component on one side of the pattern break to the lead 
of the nearest component on the other side.
Carefully crimp and solder the connections.
CAUTION: Be sure the insulated jumper wire is dressed so the 
it does not touch components or sharp edges.
- 6 -
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range
This specification is applied to the LB21B chassis.
2. Requirement for Test
Each part is tested as below without special appointment.
1) Temperature: 25 °C ± 5 °C(77 °F ± 9 °F), CST: 40 °C ± 5 °C
2) Relative Humidity: 65 % ± 10 %
3) Power Voltage
: Standard input voltage (AC 100-240 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 : CE, IEC specification
- EMC : CE, IEC 
4. Model General Specification
No.
Item
Specification
Remarks
1.
Market
Austrailia, New Zealand, Singapore, Malaysia, 
Vietnam, Indonesia,
only Analog for A-ASIA
2.
Broadcasting system
1) PAL/SECAM-B/G/D/K
2) PAL-I/II
3) NTSC-M
4) DVB-T
PAL for NZ/SG
3.
Channel Storage
ATV - 135EA, DTV - 1000EA
4.
Receiving system
Analog : Upper Heterodyne
Digital : COFDM(DVB-T)
▪ DVB-T
- Guard Interval(Bitrate_Mbit/s)
1/4, 1/8, 1/16, 1/32
- Modulation : Code Rate
QPSK     :  1/2, 2/3, 3/4, 5/6, 7/8
16-QAM  :  1/2, 2/3, 3/4, 5/6, 7/8
64-QAM  :  1/2, 2/3, 3/4, 5/6, 7/8
5.
Video(Composite) Input  PAL, SECAM, NTSC
4 System : PAL, SECAM, NTSC, PAL60
6.
Component Input 
Y/Cb/Cr, Y/Pb/Pr
7.
RGB Input 
RGB-PC
Analog (D-sub 15PIN)
8.
HDMI Input 
HDMI1-DTV/DVI
HDMI2-DTV/DVI
HDMI3-DTV
PC
- Non 3D HD/FHD Model : HDMI version 1.3
- 3D Model : HDMI version 1.4a
Support HDCP
9.
Audio Input 
RGB/DVI audio, Component, AV
10. SPDIF out 
SPDIF out
11. USB
For My Media(Movie/Photo/Music List) or SVC
12. LAN
DLNA
Only LB21B
- 7 -
5. Component Video Input (Y, P
B
, P
R
)
6. RGB (PC)
No.
Resolution
H-freq(kHz)
V-freq(Hz)
Pixel clock(MHz)
Proposed
1
720*480i
15.73
59.94
13.500
SDTV, DVD 480I(525I)
2
720*480i
15.73
60.00
13.514
SDTV, DVD 480I(525I)
3
720*576i
15.625
50.00
13.500
SDTV, DVD 576I(625I) 50Hz
4
720*480p
31.47
59.94
27.000
SDTV 480P
5
720*480p
31.50
60.00
27.027
SDTV 480P
6
720*576p
31.25
50.00
27.000
SDTV 576P 50Hz
7
1280*720
44.96
59.94
74.176
HDTV 720P
8
1280*720
45.00
60.00
74.250
HDTV 720P
9
1280*720
37.50
50.00
74.25
HDTV 720P 50Hz
10
1920*1080
28.125
50.00
74.250
HDTV 1080I 50Hz
11
1920*1080
33.72
59.94
74.176
HDTV 1080I
12
1920*1080
33.75
60.00
74.25
HDTV 1080I
13
1920*1080
26.97
23.976
63.296
HDTV 1080P
14
1920*1080
27.00
24.000
63.36
HDTV 1080P
15
1920*1080
33.71
29.97
79.120
HDTV 1080P
16
1920*1080
33.75
30.00
79.20
HDTV 1080P
17
1920*1080
56.25
50
148.5
HDTV 1080P
18
1920*1080
67.432
59.94
148.350
HDTV 1080P
19
1920*1080
67.5
60.00
148.5
HDTV 1080P
No.
Resolution
H-freq(kHz)
V-freq.(Hz)
Pixel clock(MHz)
Proposed
Remarks
1
640*350
31.468
70.09
25.17
EGA
2
720*400
31.469
70.09
28.32
DOS
3
640*480
31.469
3.
640*480
31.469
4
800*600
37.879
60.317
40
VESA(SVGA)
5
1024*768
48.363
60.004
65
VESA(XGA)
6
1360*768
47.712
60.015
84.75
VESA(WXGA)
7
1920*1080
66.587
59.934
138.50
WUXGA (Reduced Blanking)
Only FHD Model
Page of 44
Display

LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) Service Manual ▷ Download

  • DOWNLOAD LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) Service Manual ↓ Size: 5.03 MB | Pages: 44 in PDF or view online for FREE
  • Here you can View online or download the Service Manual for the LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) in PDF for free, which will help you to disassemble, recover, fix and repair LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) LCD. Information contained in LG 55LM4610 / 55LM4650 (CHASSIS:LB21B) Service Manual (repair manual) includes:
  • Disassembly, troubleshooting, maintenance, adjustment, installation and setup instructions.
  • Schematics, Circuit, Wiring and Block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Exploded View and Parts List.