DOWNLOAD LG 22LH250C (CHASSIS:LD91Z) Service Manual ↓ Size: 6.95 MB | Pages: 76 in PDF or view online for FREE

Model
22LH250C (CHASSIS:LD91Z)
Pages
76
Size
6.95 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD
File
22lh250c-chassis-ld91z.pdf
Date

LG 22LH250C (CHASSIS:LD91Z) Service Manual ▷ View online

- 4 -
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
module 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
explosion 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 easily
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
damage 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.
Alternatively, obtain and wear a commercially available
discharging wrist strap device, which should be removed to
prevent potential 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
exposure 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
electrically 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
replacement 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
sufficient 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 1.25cm) 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
component 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.
SERVICING PRECAUTIONS
- 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
circuit 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
possible 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
connections).
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
connected 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.
4. Electrical specification
- Module General Specification
1. Application range
This specification is applied to the LCD TV used LD91Z chassis.
2. Requirement for Test
Each part is tested as below without special appointment.
1) Temperature :  25±5ºC (77±9ºF), CST : 40±5ºC
2) Relative Humidity :  65±10%
3) Power Voltage : Standard input voltage (100-240V@50/60Hz)
* 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/EN60065
- EMC:CE, IEC 
No.
Item Specification
Remark
1
Screen Device
22” wide color display module
LCD
2
Aspect Ratio
16:9
3
LCD Module 
22” TFT LCD HD 
LGD/AUO/CMO
4
Storage Environment 
Temp. : -20 ~ 60 deg
Humidity : 10 ~ 90 %
5
Input Voltage 
AC100-240V~, 50/60Hz
6
Power Consumption
LGD
Typ : 26.05W
LCD(Module) + Backlight(Lamp)
AUO
Typ : 29.27W, Max : 32.425W
7
Module Size
501 (H) x 297 (V) x 17.3 (D)
8
Pixel Pitch
LGD
0.1165(H) x 0.3495(V) x RGB
AUO/CMO
0.1165(H) x 0.3495(V)
9
Back Light
CCFL
10
Display Colors
1.06Billion(FHD LGD),16.7M (others)
11
Coating
3H, AG
5. Module optical specification
(1) LGD
1) Standard Test Condition (The unit has been ‘ON’)
2) Stable for approximately 30 minutes in a dark environment at 25±2ºC.
3) The values specified are at approximate distance 50Cm from the LCD surface
4) Ta=25±2°C, VLCD=12.0V, fV=60Hz, Dclk=74.25MHz VBR_A=1.65V,ExtVBR_B=100%
(2) AUO
1) Standard Test Condition (The unit has been ‘ON’)
2) Stable for approximately 30 minutes in a dark environment at 25±2ºC.
3) The values specified are at approximate distance 50Cm from the LCD surface
4) Ta=25±2°C, VLCD=12.0V, fV=60Hz, Dclk=74.25MHz VBR_A=1.65V,ExtVBR_B=100%
No.
Item Specification
Min.
Typ.
Max.
Remark
1.
Viewing Angle [CR>10]
Right/Left/Up/Down
170(55)
Degree
2.
Luminance Luminance 
(cd/m
2
)
280
350
Variation -
1.3 
MAX/ 
MIN
3.
Contrast Ratio 
CR 
700
1000
4.
CIE Color Coordinates   
White 
Wx
0.285 
Wy 0.293
Typ 
RED Xr
0.642
±0.03
Yr
0.333
Green Xg
0.295
Yg
0.608
Blue Xb
0.147
Yb
0.063
- 7 -
No.
Item Specification
Min.
Typ.
Max.
Remark
1.
Viewing Angle [CR>10]
Right/Left/Up/Down
176
Degree
2.
Luminance Luminance 
(cd/m
2
)
300
350
Variation -
1.3 
MAX/ 
MIN
3.
Contrast Ratio 
CR 
1600
2000
4.
CIE Color Coordinates   
White 
Wx
0.295 
Wy 0.305
Typ 
RED Xr
0.640
±0.03
Yr
0.330
Green Xg
0.290
Yg
0.600
Blue Xb
0.150
Yb
0.060
Page of 76
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LG 22LH250C (CHASSIS:LD91Z) Service Manual ▷ Download

  • DOWNLOAD LG 22LH250C (CHASSIS:LD91Z) Service Manual ↓ Size: 6.95 MB | Pages: 76 in PDF or view online for FREE
  • Here you can View online or download the Service Manual for the LG 22LH250C (CHASSIS:LD91Z) in PDF for free, which will help you to disassemble, recover, fix and repair LG 22LH250C (CHASSIS:LD91Z) LCD. Information contained in LG 22LH250C (CHASSIS:LD91Z) 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.