REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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Thursday 31 December 2020

REPAIRING / SERVICING TV LG 55UK6200PLA

 Technical description and composition of LG 55UK6200PLA TV, type of panel and modules used. Module composition.

LG LED
Model: 55UK6200PLA

Chassis/Version: EAX67872805

Panel: HC550DGG-SLUL5-A14X.

LED backlight: ARRAY_REV0.0_180628_3PCM00796A

LED driver (backlight): integrated into PSU

PWM LED driver: LC5910

MOSFET LED driver: TO-252

Power Supply (PSU): EAX67865201 LGP55TJ-18U1

PWM Power: PFC, PWM

MOSFET Power: TO-252

MainBoard: EAX67872805 (1.1) EBT65339503

MainBoard IC: CPU, eMMC, DRAM, AUDIO, DC/DC

MainBoard: TDJA-G601D

Specifications 55UK6200
LG 55UK6200PLA
General recommendations for LCD LED TV repair
Possible Manifestations of Defects

- LG 55UK6200PLA does not turn on, the indicators on the front panel are not lit or blinking. TV on the control buttons and remote does not respond.

With such manifestations usually fails power module EAX67872805. In the absence of the necessary supply voltages in the secondary circuits of the converters, you must check the power switches (TO-252) and rectifier diodes for possible partial or complete breakdown.
If the diodes in the secondary circuits breakdown, the inverter can operate in the emergency short-circuit mode without output voltages, and if the power elements in the primary circuit are shorted, the mains fuse and/or the current sensor at the source of the key usually break down.
Breakdown of power switches (MosFet) in pulse sources is sometimes caused by faults in other circuit elements, e.g. in the circuits supplying the PWM controller, frequency-retaining or damping circuits, as well as in the Negative Feedback Stabilization (NFRS) circuits. PWM regulators (PFC) PFC, PWM, if they do not have visible case damage and outright short circuit between pins, are usually checked by replacement.

- No picture, sound is present, the remote control responds, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.

In some of these cases, the fault is caused by the lack of backlighting of the display. Often the cause is a faulty LED (breakage, short circuit...), or connectors of ARRAY_REV0.0_180628_3PCM00796A strips, less often faulty is the LED-driver.
It is better to use a power supply with a maximum voltage of 200V to check the condition of the LED circuit. It is not recommended to use any voltage source for this purpose. You can check each LED individually with a simple Chinese multimeter (9 volt) in P-N junction mode. If you connect the red probe of the multimeter to the anode of the LED and the black to its cathode, then the 3 volt LED will light up slightly and in the opposite direction you will find the faulty junction of the stabilizer. The functionality of the PN junction of the stabilizing diode is indirectly an indication of the functionality of the LED.

- LED blinks or lights constantly, TV set does not turn on, remote control is unresponsive.

Repair or diagnostic of motherboard EAX67872805 should begin with checking the stabilizers and power converters necessary to power the chips and matrix. If necessary, software (software) should be updated or replaced. If you try to repair the MB board (SSB), it is necessary to check the functionality of its elements - CPU, eMMC, DRAM, AUDIO, DC/DC that may need to be replaced with new ones. If you have a BGA processor, there is a possibility that the solder contacts of the BGA processor may be broken with the board (this can be done by warming it up).

Before replacing the TDJA-G601D tuner, if there is no tuning to the channels, you must first check the software and the power supply voltage on its outputs. Also you need to check if the tuner and the CPU can communicate through the I2C bus.

Warning to the users! Independent repair of LG 55UK6200PLA TV without the relevant qualification and necessary experience can lead to its complete unrepairability!

 DOWNLOAD SCHEMATIC DIAGRAM BACKLIGHT DRIVER  ------------------>   LC5910S

 

Repair after repair of backlight. Information from the master.

Decrease backlight current from 480 mA to 250 mA - replaced the resistor (current sensor) R801 1 Ohm with 1.5 Ohm on the power supply board EAX67865201.
Backlight driver current limitation. LC5910. General recommendations.

To reduce the backlight current in LED drivers with the LC5910 step-down controller, you can proportionally increase the current sensor resistance at the source of the converter power switch.

 

The appearance of the MainBoard EAX67872805 is shown in the figure below:

EAX67872805





MainBoard Appearance

The main features of the LG 55UK6200PLA:

HC550DGG-SLUL5-A14X matrix (LED panel) is installed.
For the power supply of backlight LEDs used converter, combined with a power supply, controlled by LC5910 PWM-controller. As the power elements of the LED-driver switches of TO-252 type are used.
Formation of necessary supply voltages for all LG 55UK6200PLA TV nodes is made by the power module EAX67865201, or its analogues using PFC, PWM and power switch type TO-252.
MainBoard - the main board (motherboard) is an EAX67872805 module, using CPU, eMMC, DRAM, AUDIO, DC/DC and other chips.
The TDJA-G601D tuner provides TV program reception and channel tuning.


Instructions and updates

There are downloadable files for the 55UK6200PLA model from the manufacturer:

Update and instruction files:
File Description File Name Type Date Size
SW File (Version 05.20.15) . TV_Software_Update_Guide_v3.pdf PDF 11.11.2020 2014K update instructions
SW File (Version 05.20.15) . Firmware (USB) Software_File(Version_05.20.15).zip zip 11.11.2020 884809K
Compatible with 43UK6200PLA, 43UK6300LLB, 43UK6300MLB, 43UK6300PLB, 43UK6390PLG, 43UK6400PLF, 43UK6450PLC, 43UK6470PLC, 43UK6500LLA, 43UK6500MLA, 43UK6500PLA, 43UK6510PLB, 43UK6550PLD, 43UK6710PLB, 43UK6750PLD, 43UK6950PLB, 49UK6200PLA, 49UK6300MLB, 49UK6300PLB, 49UK6390PLG, 49UK6400PLF, 49UK6450PLC, 49UK6470PLC, 49UK7500PLC, 49UK7550LLA, 49UK7550MLA, 49UK7550PLA, 50UK6300LLB, 50UK6300MLB, 50UK6300PLB, 50UK6410PLC, 50UK6470PLC, 50UK6500LLA, 50UK6500MLA, 50UK6500PLA, 50UK6510PLB, 50UK6710PLB, 50UK6750PLD, 50UK6950PLB, 55UK6200PLA, 55UK6300LLB, 55UK6300MLB, 55UK6300PLB, 55UK6400PLF, 55UK6470PLC, 55UK6500LLA, 55UK6500MLA, 55UK6500PLA, 55UK6510PLB, 55UK6550PLD, 55UK6710PLB, 55UK6750PLD, 55UK6950PLB, 55UK7500PLC, 55UK7550LLA, 55UK7550MLA, 55UK7550PLA, 60UK6200PLA, 65UK6300LLB, 65UK6300MLB, 65UK6300PLB, 65UK6400PLF, 65UK6450PLC, 65UK6470PLC, 65UK6500MLA, 65UK6500PLA, 65UK6710PLB, 65UK6750PLD, 65UK6950PLB, 65UK7550LLA, 65UK7550MLA, 65UK7550PLA, 70UK6500PLB, 70UK6710PLA, 70UK6950PLA, 75UK6200PLB, 75UK6500PLA, 75UK6750PLB.

Manuals and User Manuals:
Document Language Date Size
Quick Start Guide English - English,Estonian,Latvian,Lettish,Lithuanian,Russian 09.03.2020 56 324K
Quick Start Guide English - English,Estonian,Latvian,Lettish,Lithuanian,Russian 09.03.2020 No data
Quick start guide English - English 10.30.2018 4067K

You can download the files from the manufacturer's website for the model 55UK6200PLA.

LG 55UK6200 TV with HC550DGG-SLUL5-A14X LCD screen, measuring 54.6" (139 cm) diagonally in 16:9 aspect ratio. The LCD panel implements the principle of direct backlighting of the display with the rear arrangement of LEDs - Direct LED.
HC550DGG-SLUL5-A14X matrix and MainBoard software EAX67872805 are able to realize the image in the highest quality UHD at 3840x2160 pixels in 4K UHD, HDR standard. Image processing is made by modern technology High Dynamic Range (HDR) with an extended range of brightness gradation.
The model of TV 55UK6200 has built-in software (software) SMART and installed the operating system webOS. Connection to the network can be made via Wi-Fi. Supported media formats: MP3, WMA, MPEG4, HEVC (H.265), DivX, MKV, JPEG.
The sound speaker system has a capacity of 20 W (2x10 W) and is equipped with two loudspeakers. NICAM stereo sound processing system and Sound Surround surround function are used.
Communication with other devices via an external interface is supported by standard inputs and outputs: antenna input (RF), AV, component, HDMI x3, USB x2, Ethernet (RJ-45), Bluetooth, Wi-Fi 802.11ac, Miracast. The digital tuner is capable of receiving TV channels in DVB-T, DVB-T2, DVB-C, DVB-S, DVB-S2 standards.

The TV uses the EAX67865201 power supply.

Overall dimensions: with stand 1247x783x235 mm, without stand 1247x728x88 mm.

TV weight: with stand: 13.3 kg, without stand: 13.2 kg.

Warning. The panel HC550DGG-SLUL5-A14X of LG 55UK6200 LED TV is an expensive and unreliable element of the TV.
Do not allow any impact on the glass and pressure on the screen surface to avoid damaging the LED panel!
Also it is not safe to get liquid on the screen. Sometimes one drop is enough if it drips down the glass onto the cables and the TV becomes unrepairable.

Posted By: FRANK at 01:10
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