Tuesday 24 March 2020

REPAIR / SERVICING TV BBK 50LEX-6027

Technical description and composition of the BBK 50LEX-6027 TV, panel type and applicable modules. The composition of the modules.
BBK LED
Model: 50LEX-6027 / UTS2C
Chassis / Version: CV538H-A
Panel: V500DJ6-QE1
LED driver (backlight): integrated into PSU
Power Supply (PSU): LK-PL580405D
MainBoard: CV538H-A B538H-50UD - I
IC MainBoard: CPU: MSD6586PYE-8-SW, EMMC: KLM8G1GEME
Tuner: DVB-T2 & SAT
Technical Specifications 50LEX-6027 / UTS2C
BBK 50LEX-6027
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK 50LEX-6027 TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
Most often, with such manifestations, the main power module LK-PL580405D is found to be faulty. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM microcircuits are usually checked by replacement with new ones, or obviously working.
- There is no image, there is sound, all other functions of the TV work. When turned on, the image may sometimes appear for a second.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. The reason can sometimes be in the power of the LEDs, but more often in their malfunction (breakdown or break), sometimes in the violation of the contact connections of the LED strips.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the CV538H-A 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: MSD6586PYE-8-SW, EMMC: KLM8G1GEME 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.
The malfunction of the DVB-T2 & SAT tuner is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
We recommend the owners of the 50LEX-6027 TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!



The appearance of the MainBoard CV538H-A is shown in the figure below:
CV538H-A
Main features of the BBK 50LEX-6027 device:
Installed matrix (LED-panel) V500DJ6-QE1.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the TV BBK 50LEX-6027 is carried out by the power module LK-PL580405D, or its analogues.
MainBoard - the main board (motherboard) is a CV538H-A module using CPU chips: MSD6586PYE-8-SW, EMMC: KLM8G1GEME and others.
The DVB-T2 & SAT tuner provides TV reception and channel tuning.


Trademark: BBK, Model: 50LEX-6027 / UTS2C.
Briefly from the TV: LCD, LED backlight, 49.5 ", 3840x2160, 4K UHD, HDR, there is a satellite tuner, sound: 16W, HDMI: 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 CV538H-A B538H-50UD - I and LCD-panel V500DJ6-QE1.
Power Supply Unit (PSU) LK-PL580405D Power Supply.
BBK 50LEX-6027 / UTS2C LED TV with a 49.5 "(126 cm) diagonal LCD display with a 16: 9 aspect ratio. The required screen brightness of 250 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 4500: 1. LED display technology is implemented in the model’s display manufacturing technology. Movies can be watched in the highest possible UHD quality with 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 gradations brightness.
50LEX-6027 / UTS2C 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, WMA, MPEG4, HEVC (H.265), MKV, JPEG.
The power of the sound system 16 W (2x8 W) provides 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 x2, audio x2, component, VGA, HDMI x3, USB x2, Ethernet (RJ-45), Wi-Fi 802.11n. An output for connecting headphones is provided. The digital tuner is capable of receiving television channels in the standards DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2.
Overall dimensions: with stand 1131x721x254 mm, without stand 1131x659x93 mm.
The mass of the TV: 10.4 kg.
Attention! The BBK 50LEX-6027 / UTS2C LED TV panel 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.