Friday, 8 January 2021

REPAIRING / SERVICING TV SAMSUNG UE43NU7092U

Technical description and composition of the SAMSUNG UE43NU7092U TV, type of panel and modules used. Module
composition.

SAMSUNG LED
Model: UE43NU7092U

Chassis/Version: KANT-SU NU7090

Panel: CY-NN043HGEV6H // CY-NN043HGEVDH

LED driver (backlight): integrated into MainBoard

PWM LED driver: SLM4281B

MOSFET LED driver: TO-252

Power Supply (PSU): integrated into MainBoard

PWM Power: PFC, PWM (16pin)

MOSFET Power: N-FET TO-252

MainBoard: NU7090 BN9646782A

IC MainBoard: EEPROM: FM24C512D, eMMC: KLM4G1FETE, SPI Flash: CD25Q40C

You can use the: BN40-00330B

Specifications UE43NU7092U
SAMSUNG UE43NU7092U
General advice for LCD LED TV repair
Possible faults

- SAMSUNG UE43NU7092U does not turn on or does not show any signs of working. It doesn't blink or respond to control buttons.

In this case the main power supply unit (AC/DC converter) may be defective, as its elements in this model are located on the common MainBoard NU7090. Then we recommend to measure its output voltages and, in case of their absence, to check the serviceability of power switches (N-FET TO-252) and rectifier diodes of converters for possible short circuit.
When semiconductors in the secondary circuits of any inverter breakdown, it can usually operate in the faulty short-circuit mode without output voltages, while a short circuit in the primary circuit elements most often immediately blows the mains fuse and less often the current sensor at the source of the switch.
The breakdown of Mos-Fet switches used in switching supplies is often caused by faults in other elements, e.g. in the PWM controller supply circuit, in the frequency-retaining or damping circuits, and in the Negative Feedback Stabilisation. PWM PFC, PWM (16pin) chips are usually checked by replacing with new or known good ones.

- No display, screen is black, there is sound, with external screen light you can sometimes see faint outlines of the image.

In such cases it is more likely that the LED panel backlight elements are defective. Often the cause is a lack of current in the LED circuit, e.g. a breakage or short circuit of the LEDs, or a malfunction in the connector pins of the strips.
It is better to use a power supply with a maximum voltage of 200V to check the LED circuit. We do not recommend the use of any voltage sources 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 probe to its cathode, the 3 V LED will light up slightly and in the opposite direction you can find the junction of the faulty regulator. The functionality of the PN junction is indirectly an indication of the functionality of the LED.

- The TV set does not go into operation and the remote control is unresponsive. Front LED is either on continuously or is blinking.

If the SAMSUNG UE43NU7092U has no picture but sound, often the display backlight CY-NN043HGEVDH simply does not work. In LED TVs, the LEDs inside the panel usually fail, less often the LED driver.
In such cases, you may see a faintly visible image when ambient light hits the screen.

Disassembly of the CY-NN043HGEVDH LCD panel is required to replace the LEDs, a process that requires a skilled technician's expertise. Do not attempt this work yourself to owners of the TV and craftsman with no experience in LCD panel repair

If there is no image, but backlighting works - the screen becomes slightly lighter when the TV is switched on and you can see the light through the holes in the panel body when the TV is open.
In this case the panel may be defective - damage to the boards, cables, for example, as a consequence of moisture after an unsuccessful washing of the screen, the T-CON board (Timing Controller) may be defective. But quite often the MainBoard NU7090 is defective and so is the software.
The first items to check are the panel supply voltage, the fuses on the T-CON board, and the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, an oscilloscope should be used to monitor the LVDS signals from the NU7090 MainBoard, as well as the timing signals to the driver stubs.

The LED TV screens that have been flooded or washed unsuccessfully can be repaired in about half of the cases, usually if there is no significant damage to the panel stubs and slats.
Repair or diagnostic of NU7090 mainboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. Software (software) should be updated or replaced if necessary. Sometimes elements of MainBoard should be checked or replaced (if necessary) - EEPROM: FM24C512D, eMMC: KLM4G1FETE, SPI Flash: CD25Q40C. In cases where a BGA processor is used, the fault is usually detected by local heating.

Before replacing the BN40-00330B tuner, if it is not possible to tune to TV channels, make sure that the supply voltages are available and measure at the respective pins of the tuner and check the software for correctness. The tuner-to-processor communication pulses can be checked with an oscilloscope

Please note! The attempts to repair TV SAMSUNG UE43NU7092U, in absence of the necessary skills and experience, is strongly not recommended and is fraught with negative consequences, up to the complete unrepairability of the device!

Repair after repair of backlight. NU7090 BN9646782A and SLM4281B. Information from the master.

Reduced backlight current from 340 mA to 220 mA - replaced resistor R9201 1.7 Ohm with 2.7 Ohm in the driver current sensor on the BN9646782A board.


More on the repair of the MainBoard

The MainBoard NU7090 is shown in the illustration below:

NU7090




The main features of SAMSUNG UE43NU7092U:

A matrix (LED panel) CY-NN043HGEV6H or CY-NN043HGEVDH is installed.
A converter coupled with NU7090 main board and controlled by SLM4281B PWM controller is used for power supply of backlight LEDs. A TO-252-type switch is used as the power element of the LED driver.

The power supply module is combined with the MainBoard and is designed as an AC/DC reverse converter using PFC, PWM (16pin) chips and N-FET TO-252 type power switches.
MainBoard - the main board (motherboard) is NU7090 module, with EEPROM: FM24C512D, eMMC: KLM4G1FETE, SPI Flash: CD25Q40C and others.
The BN40-00330B tuner provides TV programme reception and channel tuning.

Manuals and updates

For UE43NU7092UXXH there are files for download:

Latest software updates, firmwares (latest firmwares):
File type File name Version Date Size
Upgrade instructions 2018_TV_Firmware_Upgrade_Instruction_T-KTSUDEUC.pdf 1.0 23.06.2020 0.48 Mb
Upgrade File (USB) T-KTSUDEUC.zip 1310.4 02.11.2020 1076.41 Mb
Upgrade File (USB) T-KTSUDEUC_1310.4.exe 1310.4 02.11.2020 1076.18 Mb

User Manuals and Guides:
File type File name Version Date Size
User Manual BN68-09160E-00_UNU7090P_XH_L16_180525.0.pdf 00 26.07.2018 8.32 Mb
PDF manual ENG_KM2DVBEUN-3.0.2_181205.0.pdf 3.0.2 02.01.2019 11.33 Mb


You can download the files for the model UE43NU7092UXXH from the manufacturer's website.

 

The SAMSUNG UE43NU7092U LCD TV CY-NN043HGEVDH measures 42.5" (108cm) diagonally and has a 16:9 aspect ratio. This model uses an Edge LED panel in the backlighting of the display.
CY-NN043HGEVDH matrix and MainBoard NU7090 software are capable of realizing maximum image quality of UHD at 3840x2160 pixels in 4K UHD, HDR. Advanced High Dynamic Range (HDR) image processing with an extended brightness gradation range.
The UE43NU7092U features embedded SMART software with the Tizen Operating System. Network connectivity can be achieved via Wi-Fi. Supported media formats are MP3, WMA, MPEG4, HEVC (H.265), DivX, MKV, JPEG.
The sound system has a capacity of 20 W (2x10 W) and is powered by two loudspeakers. NICAM stereo sound processing and Sound Surround surround function are used.
Communication with other devices via an external interface is supported by standard input and output connectors: antenna input (RF), HDMI x2, USB, Ethernet (RJ-45), Wi-Fi 802.11n, Miracast. The digital tuner is capable of receiving DVB-T, DVB-T2, DVB-C, DVB-S and DVB-S2 TV channels.

Power consumption in mains mode is 120 W. Power supply as part of MainBoard.

Dimensions: with stand 970x605x207mm, without stand 970x563x59mm.

TV weight: with stand 9.7kg, without stand 9.6kg.

Warning. The CY-NN043HGEVDH panel on the SAMSUNG UE43NU7092U LED TV is an expensive and fragile part of the TV.
Avoid all impacts to the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also not safe to get liquids on the screen. Sometimes one drop is enough if it drips down the glass onto the cables and the television becomes unrepairable.