"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.
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.
SOFTWARE UPDATE
USB
(1) Insert the USB memory Stick to the USB port
(2) Automatically detect the SW Version.
(3) Click [YES]: initiate the download and install of the update.
(4) Click [Check Now]: move to “About This TV” page for update
(5) TV is updating.
(6) After finished the update, Pop-up appear.
(7) Click [Yes] : TV will be DC OFF -> ON
(8) After TV turned on, Check the updated SW Version and Tool Option.
Click on the pictures to zoom in
NSU
(This Function is needed to connect to the internet)
(1) Menu -> All Settings -> General -> About This TV.
(This Function is needed to connect to the internet)
(1) Menu -> All Settings -> General -> About This TV.
(2)
Click [CHEK FOR UPDATES] : system check latest version.
(3)
Click [DOWNLOAD AND INSTALL]
(4) TV is updating
(4) TV is updating
(5)
After finished the update, Pop-up
appear.
(6)
Turn OFF the TV and On. Check the updated SW Version and Tool Option.
Standard
Repair Process Detail
Video
error_No video/Normal audio
Check
White Balance value
To enter
the service mode.
You need a special
remote control to do this. You can buy
it from the authorized service center for LG.
The remote control is called “Service remote control”. There is no other way to get into the service
mode of LG TVs, whichever may its model or type. This special remote control can be used with
all LG brand TVs, to enter the service mode. (If the authorised service center refuses to give it to you, {this will be the case, always. It is a business trick.}, you can buy it by online).
Search for it online. It is available.
Entry
method
1. Press the ADJ button on the remote control for adjustment.
2. Enter into White Balance of item 12.
3. After recording the R, G, B (GAIN, Cut) value of Color Temp (Cool/Medium/Warm), re-enter the value after replacing the MAIN BOARD.
1. Press the ADJ button on the remote control for adjustment.
2. Enter into White Balance of item 12.
3. After recording the R, G, B (GAIN, Cut) value of Color Temp (Cool/Medium/Warm), re-enter the value after replacing the MAIN BOARD.
Video error_Video error, video lag/stop
TUNER input signal strength checking method
All Settings > Channels > Channel Tuning > Manual Tuning
When the signal is strong, use the attenuator (-10dB, - 15dB, -20dB etc.)
Video
error_Video error, video lag/stop
OLED
TV Version checking method
Checking
method for remote control for adjustment
Press
the IN-START with the remote control for adjustment.
Video
error_Video error, video lag/stop
TUNER
checking
1.
Check the signal strength or check whether the screen is normal when the
external device is connected.
2. After measuring each voltage from power supply, finally replace the MAIN BOARD.
2. After measuring each voltage from power supply, finally replace the MAIN BOARD.
Video error _Vertical/Horizontal bar, residual image, light spot
As the part connecting to the external input, check the screen condition by signal.
Video
error_Color error
Check
Link Cable (Vx1) reconnection condition.
Check
the contact condition of the Link Cable, especially dust or mis insertion
Screen
appearance – Main board faults
Module
fault. Un-repairable Cases. In this case
please exchange the module.
Power error _No power
Check power input voltage and ST-BY 3.5V
Power
error _Off when on, off whiling viewing
POWER
OFF MODE checking method
1.
Press the IN-START button of the remote control for adjustment
2. Check the entry into adjustment item 3 (Power On/Off Status)
2. Check the entry into adjustment item 3 (Power On/Off Status)
Audio error_No audio/Normal video
Checking method in menu when there is no audio
1. Press the Setting button on the remote control
2. Select the Sound function of the Menu
3. Select the Sound Out
4. Select TV Speaker.
Voltage
and speaker checking method when there is no audio
Check
the contact condition of or 20V connector of Main Board
Measure the 20V input voltage supplied from Power Board (If there is no input voltage, remove and check the connector)
Connect the tester RX1 to the speaker terminal and if you hear the Chik Chik sound when you touch the GND and output terminal, the speaker is normal.
Measure the 20V input voltage supplied from Power Board (If there is no input voltage, remove and check the connector)
Connect the tester RX1 to the speaker terminal and if you hear the Chik Chik sound when you touch the GND and output terminal, the speaker is normal.
Function
error
Remote
control operation checking method
1.
Check IR cable condition between IR & Main board.( Check picture number①
and ②)
2. Check the standby 3.5V on the terminal 16 pin (③)
3. AS checking the Pre-Amp(IR LED light) , the power is in ON condition, an Analog Tester needle should move slowly, otherwise, it’s defective.
2. Check the standby 3.5V on the terminal 16 pin (③)
3. AS checking the Pre-Amp(IR LED light) , the power is in ON condition, an Analog Tester needle should move slowly, otherwise, it’s defective.
Motion Remote operation checking method
Checking order to check motion remote/wifi
1.Check BT/Wifi cable condition between BT/Wifi assy & Main board.
2.Check the 3.5V on the terminal 19.
Video error_Color error
Adjustment Test pattern
Press the P-ONLY > HDMI HOT > CH + or -
You can view 11 types of patterns using the CH+ or - key
Checking item :
1. Defective pixel
2. Residual image
3. MODULE error (ADD-BAR,SCAN BAR..)
4.Video error (Classification of MODULE or Main-B/D)
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.
