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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Monday 23 March 2020

REPAIR / SERVICING TV BBK 32LEX-7047

Technical description and composition of the BBK 32LEX-7047 TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: 32LEX-7047 / T2C
Chassis / Version: CV338H-U42
Panel: PT320AT01-1
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267
MOSFET LED driver: AOD4454
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: 7N60
MainBoard: CV338H-U42
IC MainBoard: CPU: MSD6A338, SPI Flash: 25Q16
Tuner: R842
Specifications 32LEX-7047 / T2C
BBK 32LEX-7047
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK 32LEX-7047 TV does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
In this case, the main Switching Power Supply, an AC / DC network voltage converter, whose elements are located on the MainBoard CV338H-U42 main board, may be faulty. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of power switches (7N60) of converters and rectifier diodes for the presence of a possible short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency-setting or damper ones, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) PWM SOT23-6, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, the screen is black, there is sound, with external illumination of the screen, you can sometimes see barely noticeable outlines of the image.
The most likely in these cases is a malfunction of the LED backlight. The reason may be a break in the LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the thong connectors,
To check the health in the LED circuit it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the CV338H-U42 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Board repair and replacement of CPU chips: MSD6A338, SPI Flash: 25Q16 are carried out with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
In cases where there is no tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the R842 tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Once again, remind users! Attempts to independently repair the BBK 32LEX-7047 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


The appearance of the MainBoard CV338H-U42 is shown in the figure below:

CV338H-U42
Main features of the BBK 32LEX-7047 device:
Installed matrix (LED panel) PT320AT01-1.
To power the backlight LEDs, a converter is used, combined with the main board CV338H-U42, controlled by a BIT3267 PWM controller. As power elements of the LED driver, keys of the AOD4454 type are used.
The power module is combined with the MainBoard and is made according to the scheme of a flyback AC / DC voltage converter using PWM SOT23-6 microcircuits and 7N60 type power switches.
MainBoard - the main board (motherboard) is a CV338H-U42 module, using CPU chips: MSD6A338, SPI Flash: 25Q16 and others.
The R842 tuner provides TV reception and channel tuning.
Brand: BBK, Model: 32LEX-7047 / T2C.
Shortly from the TV: LCD, 31.5 ", 1366x768, 720p HD, DVR, sound: 16 W, HDMI connectors: 3, Internet access, Wi-Fi, Smart TV.
Manufacturer: TELEBALT Kaliningrad, Kamskaya, 62. The assembly can be in the city of Guards, st. Station, 6 (PKV).
Developer: BBK Electronics LTD. China
The composition uses MainBoard CV338H-U42 and LCD-panel PT320AT01-1. The power supply is combined with the MainBoard.
BBK 32LEX-7047 / T2C LED TV with PT320AT01-1 LCD display, diagonal size 31.5 "(80 cm) in 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlight LED. The ratio of maximum brightness to minimum ( contrast ratio) is 1400: 1. LED model LED backlighting is implemented in the model’s display technology.
32LEX-7047 / T2C has built-in SMART Software and pre-installed Android Operating System. Connecting to the Internet can be done via Wi-Fi. Supported media file formats: MP3, MPEG4, HEVC (H.265), MKV, JPEG.
The power of the sound speaker system 16 W (2x8 W) is provided by two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, VGA, HDMI x3, USB x2, Ethernet (RJ-45), Wi-Fi 802.11n. An output for connecting headphones is provided. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 735x461x179 mm, without stand 735x433x74 mm.
Mass of the TV: 6.1 kg.
Attention! The panel of the PT320AT01-1 LED TV BBK 32LEX-7047 / T2C is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.

Posted By: FRANK at 05:51
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