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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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Tuesday, 15 September 2020

REPAIRING / SERVICING TV SAMSUNG UE55NU7090U

Technical description and composition of the SAMSUNG UE55NU7090U TV, panel type and modules used. The composition of the modules.
SAMSUNG LED
Model: UE55NU7090U
Chassis / Version: FB01
Panel: CY-NN055HGLVCH
LED backlight: BN96-45913A NU7100_STS550AU9_40LEDs_3030F_2C_Rev1.0
LED driver (backlight): integrated into PSU
MOSFET LED driver: TO-252
Power Supply (PSU): BN44-00932C L55E6_NHS
PWM Power: PFC, PWM
MOSFET Power: TO-220
MainBoard: BN41-02662A BN94-12869
IC MainBoard: Audio: TAS5745
Tuner: BN40-00331B
Control: IR & Butoon: BN96-45912A Y18 VNB. V2.0 (CT180703)
UE55NU7090U Specifications
SAMSUNG UE55NU7090U
General recommendations for TV LCD LED repair
Possible malfunctions
- SAMSUNG UE55NU7090U does not turn on, does not respond to buttons and the remote control, indicators on the front panel do not light or flash.
In such cases, the BN44-00932C power supply usually fails. It is necessary to measure its output voltages, and in the case of their absence (full or partial), the serviceability of the power switches (TO-220) of the converters and rectifier diodes should be checked for a possible short circuit.
In case of any breakdowns of semiconductors in the secondary circuits, the converter can usually operate normally in an emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and, less often, the current sensor in the source of the key.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers PFC, PWM, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or knowingly working properly.
- There is no image, there is sound, it reacts to the remote control, the channels are switched. In some cases, the image appears when turned on and disappears immediately.
Most likely in these cases is a malfunction of the LED panel backlight. The reason can sometimes be in the power supply of the LEDs, but more often in their malfunction (breakdown or breakage), sometimes in the violation of the contact connections of the LED strips.
When trying to detect a break in the LED lines, you should take into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.

Repair or diagnostics of the BN41-02662A 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). Repair of the board and replacement of Audio: TAS5745 microcircuits are made if the necessary equipment and the corresponding element base are available. Failures associated with the use of BGA soldering technologies can be localized by warming up.

Before changing the BN40-00331B tuner, if it is not possible to tune to TV channels, you should make sure that there are supply voltages, which must be measured at the corresponding tuner terminals and check the software for correctness. The pulses of data exchange between the tuner and the processor can be monitored with an oscilloscope
I remind users again! Attempts to self-repair the SAMSUNG UE55NU7090U TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


Additional MainBoard Repair
The appearance of the MainBoard BN41-02662A is shown in the figure below:
BN41-02662A
External view of the power supply
Main features of the SAMSUNG UE55NU7090U device:
Installed matrix (LED panel) CY-NN055HGLVCH.
A converter combined with a power supply is used to power the backlight LEDs. TO-252 switches are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the SAMSUNG UE55NU7090U TV is carried out by the BN44-00932C power module, or its analogs using PFC, PWM microcircuits and TO-220 power switches.
MainBoard - the main board (motherboard) is a BN41-02662A module, using Audio chips: TAS5745 and others.
The BN40-00331B tuner provides reception of television programs and tuning to channels.
There are files to download for the UE55NU7090UXRU model from the manufacturer:Latest software updates, firmware (latest firmwares):File type File name Version Date SizeUpdate instructions 2018_TV_Firmware_Upgrade_Instruction_T-KTSUDEUC.pdf 1.0 23.06.2020 0.48 MbUpdate file (USB) T-KTSUDEUC.zip 1292.1 02/18/2020 1067.72 MbUpdate file (USB) T-KTSUDEUC_1292.1_RU.exe 1292.1 18.02.2020 1067.49 MbUpdate file (USB) T-KTSUDEUC_1292.1.exe 1292.1 18.02.2020 1067.49 MbUser Manuals and Instructions:File type File name Version Date SizeUser manual BN68-09160V-00_UNU7090P_EN_L02_181211.1.pdf 00 01/24/2019 1.25 MbInstruction PDF ENG_KM2DVBEUN-3.0.2_181205.0.pdf 3.0.2 02.01.2019 11.33 MbInstruction PDF RUS_KM2DVBEUN-3.0.2_181205.0.pdf 3.0.2 02.01.2019 11.42 MbFiles can be downloaded from the manufacturer's website for the UE55NU7090UXRU model.

TV SAMSUNG UE55NU7090U with LCD CY-NN055HGLVCH, diagonal size 54.6 "(139 cm) 16: 9 format. This model uses a panel with edge LED backlighting - Edge LED.
CY-NN055HGLVCH sensor and MainBoard BN41-02662A main board 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 TV model UE55NU7090U 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), HDMI x2, USB, 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 155 W. Power supply BN44-00932C.
Dimensions: with stand 1239x757x242 mm, without stand 1239x714x59 mm.
TV weight: with stand: 17.5 kg, without stand: 17.3 kg.
Attention! Panel CY-NN055HGLVCH of LED TV SAMSUNG UE55NU7090U 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.


Posted By: FRANK at 06:42
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