Wednesday, 16 September 2020

REPAIRING / SERVICING TV SAMSUNG UE49NU7300U

Technical description and composition of the SAMSUNG UE49NU7300U TV, panel type and modules used. The composition of the modules.
SAMSUNG LED
Model: UE49NU7300U
Chassis / Version: FA01
Panel: CY-CN049HGLV2V
LED backlight: NU7100_STS490A81_38LEDS_3030F_2C_REV1.0 BN96-45953B
LED driver (backlight): integrated into PSU
Power Supply (PSU): BN44-00932B REV1.2 L55E6_NSM PSLF171301A
PWM Power: PFC, PWM
MOSFET Power: N-FET TO-220F
MainBoard: BN41-02635A BN94-12796E
IC MainBoard: CPU: SDP1711, EMMC: KLM4G1FETE, Audio: TAS5745
Tuner: BN40-00330B
UE49NU7300U Specifications
SAMSUNG UE49NU7300U
General recommendations for TV LCD LED repair
Possible manifestations of defects
- SAMSUNG UE49NU7300U does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
Often in such cases, the BN44-00932B power supply module is faulty. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches (N-FET TO-220F) and rectifier diodes in the converters for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in short-circuit mode, and in case of short-circuit in the elements of the primary circuit, the mains fuse usually breaks off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements, which can disable it in key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying a PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) PFC, PWM, in the absence of external damage and a short circuit between the terminals, are checked by replacing them with known good ones.
- There is no image, there is sound, it reacts to the remote control. Or the image may appear for a second when turned on and disappear immediately.
In some of these cases, the malfunction is caused by the lack of display backlighting. Often the reason is a malfunction of the LEDs (open circuit, short circuit ...), or the connectors of the strips (strings), less often the LED driver turns out to be faulty.
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 TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the BN41-02635A 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). If it is not possible to replace the MB (SSB) board, you must check the health of its elements - CPU: SDP1711, EMMC: KLM4G1FETE, Audio: TAS5745. Defective components must be replaced.

 If SAMSUNG UE49NU7300U has no picture, but there is sound, often the display backlight CY-CN049HGLV2V simply does not work. Moreover, in LED TVs, the LEDs inside the panel usually fail, less often the LED driver.
In such cases, you can see a barely noticeable image with a successful hit of external light on the screen.
Replacing the LEDs requires disassembling the LCD panel CY-CN049HGLV2V, a process that requires experience and qualifications from the technician. We do not recommend doing such work on your own to the owners of TVs and craftsmen who do not have experience in repairing LCD panels
If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and in an open TV you can see the light through the holes in the panel case.
In this case, the panel may also be faulty - damage to strips, loops, for example, as a result of moisture ingress after unsuccessful washing of the screen, the T-CON (Timing Controller) board may be faulty. But the main board MainBoard BN41-02635A often turns out to be faulty, a software failure is also possible.
Then, first of all, it is necessary to check the panel supply voltage, the 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 the passage of LVDS signals from the MainBoard BN41-02635A with an oscilloscope, as well as synchronization signals to the loops with drivers.
Flooded or unsuccessfully washed screens of LED-TVs can be restored, in about half of the cases, usually if significant damage has not formed in the loops and panel strips.


If 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 BN40-00330B tuner terminals. 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.
Owners and users of SAMSUNG UE49NU7300U TVs should remember that self-repair without special knowledge, skills and qualifications may be fraught with negative consequences that can lead to complete non-repairability of the device!


Additional MainBoard Repair
The appearance of MainBoard BN41-02635A is shown in the figure below:
BN41-02635A
External view of the power supply
Main features of the SAMSUNG UE49NU7300U device:
The matrix (LED-panel) CY-CN049HGLV2V 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 UE49NU7300U TV is carried out by the BN44-00932B power module, or its analogs using PFC, PWM chips and N-FET TO-220F power switches.
MainBoard - the main board (motherboard) is a BN41-02635A module, using CPU: SDP1711, EMMC: KLM4G1FETE, Audio: TAS5745 and others.
Tuner BN40-00330B provides reception of television programs and tuning to channels.


 TV SAMSUNG UE49NU7300U with LCD CY-CN049HGLV2V, diagonal size 48.5 "(123 cm) 16: 9 format. This model uses a panel with edge LED backlighting - Edge LED.
CY-CN049HGLV2V sensor and MainBoard BN41-02635A main board software are capable of realizing images in the highest UHD quality at a resolution of 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.
TV model UE49NU7300U has built-in SMART software and Tizen Operating System installed. The connection to the network can be carried out via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, HEVC (H.265), DivX, 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), 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 135 W. BN44-00932B power supply.
Dimensions: with stand 1102x717x261 mm, without stand 1102x639x96 mm.
TV weight: with stand: 13.7 kg, without stand: 13.3 kg.
Attention! Panel CY-CN049HGLV2V of SAMSUNG UE49NU7300U LED TV 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.