Friday, 29 January 2021

REPAIRING / SERVICING TV SAMSUNG UE40JU6400U

Technical description and composition of SAMSUNG UE40JU6400U TV, type of panel and modules used. Module composition.

SAMSUNG LED
Model: UE40JU6400U

Panel: CY-GJ040HGLV1V

LED backlight: LM41-00117B, LM41-00117C

T-CON: BN41-02297A BN95-01936A

LED driver (backlight): integrated into PSU

PWM LED driver: SM1251

Power Supply (PSU): BN44-00806A L40S6_FDY

PWM Power: FA6A20N, SPC7011F

MOSFET Power: K8A50D

MainBoard: BN41-02344A BN94-08217J

IC MainBoard: SPI Flash: 25Q40, SOUND: NTP7415

Temperature: BN40-00316B

Control: WiFi: BN59-01194A WCH730B

Specifications UE40JU6400U
SAMSUNG UE40JU6400U
General recommendations for LCD LED TV repair
Possible problems

- SAMSUNG UE40JU6400U TV does not turn on at all. No reaction to the remote control and the control buttons on the front panel. Indicator lights are not lit or blinking.

The power module BN44-00806A is often defective in such cases. It is necessary to measure its output supply voltages, and if they are absent check the serviceability of the power switches (K8A50D) of the converters and the rectifier diodes for the probability of breakdown in the semiconductor PN-junctions.
If there is a breakdown in the secondary circuits of the inverter, it can usually be short-circuited, and if there is a short in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key is most often blown.
Mos-Fet power switches used in switching power supplies sometimes fail due to the failure of some other element that can take it out of key mode, or cause the switch to exceed its maximum allowable parameters. These can be elements that feed the PWM controller, the frequency-retaining or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers FA6A20N, SPC7011F, if there is no visible damage or obvious short circuit between the pins, are checked by replacing with the new ones or known good ones.

If the SAMSUNG UE40JU6400U has no picture but has sound, often the CY-GJ040HGLV1H display backlight simply does not work. Moreover, in LED TVs usually fail LEDs inside the panel, less often the LED-driver.
In such cases you can see a faintly visible image when external light hits the screen.

To replace the LEDs requires disassembly of the LCD panel CY-GJ040HGLV1H - a process which requires a master of experience and expertise. We do not recommend to perform such works by yourself to owners of TV sets and craftsmen who have no experience in LCD panel repair.

READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.

If there is no image, but backlighting works - the screen becomes slightly lighter when the TV is switched on, and in the open TV you can see the light through the holes in the body of the panel.
In this case the panel may be defective - damage to the strips, 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 BN41-02344B is defective and so is the software.
Then first it is necessary to check the panel power supply voltage, fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, it is necessary to trace by oscilloscope the LVDS signals from MainBoard BN41-02344B, as well as synchronizing signals to driver stubs.

Filled or unsuccessfully washed LED TV screens can be restored in about half of the cases, usually, if there is no significant damage in the cables and panel bars.

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

As a rule, in such cases there is no display backlight. The reason could be a breakage in the circuit of the LEDs LM41-00117B, LM41-00117C, or a problem with stabilizing their power supply.
To detect breakage in the lines of LEDs without disassembling the panel you will need a power source. It is impossible to open the transitions connected in series with a simple multimeter, you need a voltage of several tens of volts.

- Indicator is blinking or glowing all the time, TV set doesn't turn on, remote control doesn't respond.

Repair or diagnosis of the motherboard BN41-02344A should begin with checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (firmware). When trying to repair MB board (SSB), you must check the functionality of its elements - SPI Flash: 25Q40, SOUND: NTP7415 that may need replacement with new ones. If you have a BGA processor, there is a possibility of breaking the soldering of its contacts with the board (this can be diagnosed by heating).

The BN40-00316B tuner malfunction is detected after checking the software and all the supply voltages on its outputs. You can check the communication between the tuner and the processor via the I2C bus with an oscilloscope.

Once again I remind the TV users: do not try to repair the TV without proper knowledge, experience and necessary qualification! Entrust the repair to professionals with sufficient experience in the field of repair of electronic equipment.

More on MainBoard Repair

The MainBoard BN41-02344A is shown in the figure below:




BN41-02344A

MainBoard Appearance

The main features of the SAMSUNG UE40JU6400U:

A matrix (LED panel) CY-GJ040HGLV1V is installed.
Timing Controller (T-CON) BN41-02297A is used to control the matrix.
The converter combined with the power supply is used to power the backlight LEDs and is controlled by the PWM controller SM1251.
The power supply module BN44-00806A or its analogues using FA6A20N, SPC7011F chips and power switches of K8A50D type provide the formation of the required supply voltages for all the nodes of SAMSUNG UE40JU6400U TV.

MainBoard - the main board (motherboard) is a module BN41-02344A, using SPI Flash chips: 25Q40, SOUND: NTP7415 and others.
The BN40-00316B tuner is used to receive TV programs and tune to channels.


Instructions and updates

There are download files for UE40JU6400UXRU from the manufacturer:

Latest software updates, firmwares (latest firmwares):
File Type File Name Version Date Size
Firmware Update User Manual 2015_TV_Firmware_Upgrade_Instruction_T-HKMDEUC.pdf 1.0 10.08.2015 0.36 Mb
Update file (USB) T-HKMDEUC_1550.0.exe 1550.0 03.12.2019 1637.59 Mb

User Manuals (User Manuals):
File Type File Name Version Date Size
ENG_HMUDVBEUJ-1.312 User Manual - 06.08.2015 7.66 Mb
Quick guide JU6400-RU_BN68-07198H-02L04-0323.pdf 1.0 26.05.2015 12.76 Mb
KINO KIT Guide VG-SWD1000-CIS-IB_Rev1.2L04-0408.pdf - 26.05.2015 2.11 Mb
Installation Guide UJ6P-JU6400-QSG_BN68-07137C-01-0311.pdf - 02.09.2015 0.01 Mb
UJ6S-JU6530-QSG_BN68-07137G-01-0311.pdf - 02.09.2015 0.01 Mb

You can download the files from the manufacturer's website for the UE40JU6400UXRU model.



SAMSUNG UE40JU6400U LCD TV CY-GJ040HGLV1H, 40" (102 cm) diagonal size 16:9. In the manufacturing technology of the display of this model is implemented LED backlighting.

Matrix CY-GJ040HGLV1H and MainBoard software BN41-02344B able to realize the image in the highest quality UHD at a resolution of 3840x2160 pixels in 4K UHD standard.

The UE40JU6400U is equipped with SMART software, built-in applications and internet connectivity. Connection to the network can be made via Wi-Fi wireless communication. Input analog video signal is decoded in PAL, SECAM, NTSC systems. Graphic processing of a digital signal is done in 480i, 480p, 576i, 576p, 720p, 1080i, 1080p, 2160p. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG.
The speaker system sound power 20W (2x10W) is provided by two speakers. NICAM STEREO audio processing system is used.
Communication with other devices via an external interface is supported by standard inputs and outputs: antenna input (RF), AV, component, HDMI x4, MHL, USB x3, Ethernet (RJ-45), Bluetooth, Wi-Fi 802.11n. A VGA (D-Sub 15) connector is provided to connect a computer or laptop to this TV model. This interface supports standard resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080, 3840x2160. Digital tuner is able to receive DVB-T, DVB-T2, DVB-C, DVB-S2 TV channels.

The power consumed by the worker in mains mode is 150 W. Power supply BN44-00806E.

Overall dimensions: with stand 918x582x241 mm, without stand 918x536x63 mm.

TV weight: with stand 9.4 kg, without stand 7.7 kg.

Warning. The panel CY-GJ040HGLV1H of the SAMSUNG UE40JU6400U LED TV is an expensive and unreliable part of it.
Do not allow any impact on the glass and pressure on the surface of the screen to avoid damage to 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.