Wednesday 16 September 2020

REPAIRING / SERVICING TV SAMSUNG UE43RU7400U

Technical description and composition of the SAMSUNG UE43RU7400U TV, panel type and modules used. The composition of the modules.
SAMSUNG LED
Model: UE43RU7400U
Panel: CY-NN043HGEVGV
LED driver (backlight): integrated into PSU
Power Supply (PSU): BN44-00947J L43E7_RSM
PWM Power: PFC, PWM
MOSFET Power: TO-252
MainBoard: BN41-02703A BN94-14799B
IC MainBoard: CPU, eMMC, DRAM, AUDIO, DC / DC
Tuner: BN40-00331B
UE43RU7400U Specifications
SAMSUNG UE43RU7400U
General recommendations for TV LCD LED repair
Possible malfunctions
- TV SAMSUNG UE43RU7400U does not turn on, does not respond to the remote control and control panel buttons, the indicators do not light up or flash.
In such cases, the BN44-00947J power supply usually fails. Its output voltages should be measured and, in their absence, the power switches and rectifier diodes should be checked for the probability of a short circuit in the converters.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work in an emergency in the short-circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Breakdown of power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) PFC, PWM, if they do not have visible damage to the case and an outright short circuit between the pins, are usually checked by replacement.
- There is no picture, but there is sound, it reacts to the remote control. Or the image appears when turned on and immediately disappears
Often in such cases, there is no backlighting of the LED panel. Often the cause of a malfunction is the lack of current in the LED circuit, for example, their open or short circuit, or a violation of the contact connections of the connectors.
To identify an open circuit in the LED lines without disassembling the panel, a current source is required. It is impossible to open the junctions connected in series with a simple multimeter; a voltage of several tens of volts is required.
- The indicator on the front panel blinks, the TV does not turn on in operating mode, does not respond to the remote control.
Repair or diagnostics of the BN41-02703A motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). When repairing an MB board, it is necessary to check its components CPU, eMMC, DRAM, AUDIO, DC / DC. Defective elements should be replaced. If chips with BGA soldering technology are used, the problem in its implementation is detected by local heating of the chip.
In cases where there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltages at the terminals of the BN40-00331B tuner. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Attention! Users and owners of UE43RU7400U TVs who do not have the appropriate qualifications, knowledge and experience are strongly discouraged from trying to repair themselves in order to avoid negative consequences that can lead to complete non-repairability of the device.

Additional MainBoard Repair
The appearance of the MainBoard BN41-02703A is shown in the figure below:
BN41-02703A
External view of the power supply
Main features of the SAMSUNG UE43RU7400U device:
The matrix (LED-panel) CY-NN043HGEVGV is installed.
A converter combined with a power supply is used to power the backlight LEDs.
The formation of the necessary supply voltages for all nodes of the SAMSUNG UE43RU7400U TV is carried out by the BN44-00947J power module, or its analogs using PFC, PWM microcircuits and power switches of the TO-252 type.
MainBoard - the main board (motherboard) is a BN41-02703A module using CPU, eMMC, DRAM, AUDIO, DC / DC and others.
Tuner BN40-00331B provides reception of television programs and tuning to channels.

There are files to download for the UE43RU7400UXRU model from the manufacturer:Latest firmware updates (latest firmwares):File type File name Version Date SizeUpdate file (USB) T-MSLDEUC.zip 1360.9 14.07.2020 1281.07 MbUpdate instruction 2019_TV_Firmware_Upgrade_Instruction_T-MSLDEUC.pdf 1.0 16.06.2020 0.49 MbUpdate file (USB) T-MSLDEUC_1360.9.exe 1360.9 07/14/2020 1280.78 MbUpdate file (USB) T-MSLDEUC_1360.9_RU.exe 1360.9 14.07.2020 1280.78 MbUser Manuals and Instructions:File type File name Version Date SizeUser manual BN68-09493G-00_URU7400G_EN_L02_190215.1.pdf 00 03/15/2019 0.81 MbBrief instructions BN68-09508A-00_QSG_URU7400G_CIS_190213.0.pdf 00 03/15/2019 0.56 MbPDF instruction MUSDVBEUR-3.0.0_EM_MUSE_EU_ENG_190820.0.pdf 3.0.0 24.10.2019 22.14 MbPDF instruction MUSDVBEUR-3.0.0_EM_MUSE_EU_RUS_190820.0.pdf 3.0.0 10.24.2019 22.12 MbFiles can be downloaded from the manufacturer's website for the UE43RU7400UXRU model.




SAMSUNG UE43RU7400U TV with LCD CY-NN043HGEVGV, diagonal size 42.5 "(108 cm) 16: 9 format. The display technology of this model implements LED backlighting.
CY-NN043HGEVGV sensor and MainBoard BN41-02703A software are capable of realizing images in the highest UHD quality at 3840x2160 pixels in 4K UHD, HDR standard. Image processing is performed using modern High Dynamic Range (HDR) technology with an extended range of brightness gradations.
The UE43RU7400U TV is equipped with SMART software, built-in applications and the ability to work on the Internet. The connection to the network can be carried out via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, HEVC (H.265), MKV, JPEG.
Speaker sound system power 20 W (2x10 W) is provided by two speakers. The NICAM stereo audio processing system and the Sound Surround function are used.
Communication with other devices via an external interface is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x3, USB x2, Ethernet (RJ-45), Bluetooth, Wi-Fi 802.11ac, Miracast.
The digital tuner can receive TV channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
The power consumed when operating from the network is 120 W. Power supply BN44-00947J.
Dimensions: with stand 970x648x344 mm, without stand 970x563x58 mm.
TV weight: with stand: 12.1 kg, without stand: 9.5 kg.
Attention! Panel CY-NN043HGEVGV LED TV SAMSUNG UE43RU7400U is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.