Monday 23 March 2020

REPAIR / SERVICING TV BBK 40LEX-5043

Technical description and composition of the BBK 40LEX-5043 TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: 40LEX-5043 / FT2C
Chassis / Version: CV338H-U42
Panel: V400HJ6-PE1
LED backlight: JS-D-JP395DM-A / B82EC (80510) E395DM1000
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 40LEX-5043 / FT2C
BBK 40LEX-5043
General repair guidelines for TV LCD LED
Possible malfunctions
- BBK 40LEX-5043 does not turn on, does not respond to buttons and remote control, indicators on the front panel do not light up and do not blink.
First of all, in such cases, you should verify the operability of the common switching power supply (IIP) - AC / DC voltage converter of the mains voltage. All source elements in this TV model are located on the MainBoard CV338H-U42 main board. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches (7N60) and the rectifier diodes of the converters for a probable short circuit.
In case of breakdowns of semiconductors in secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) PWM SOT23-6, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. 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.
When trying to detect a break in the LED lines, it should be taken 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, does not respond to the remote control. The indicator blinks or signals standby mode.
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). When repairing an MB board, you need to check its CPU components: MSD6A338, SPI Flash: 25Q16. Defective items should be replaced. If chips with BGA soldering technology are used, a problem in its implementation is detected by the local heating of the chip.
Before changing the R842 tuner, if it is not possible to tune to television channels, you should make sure that there are supply voltages that must be measured at the corresponding tuner pins and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Attention to users! Independent repair of the TV BBK 40LEX-5043 without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    BBK 32LEX-5024 Chassis CV338H-T42
 The appearance of the MainBoard CV338H-U42 is shown in the figure below:
CV338H-U42
Main features of the BBK 40LEX-5043 device:
Installed matrix (LED-panel) V400HJ6-PE1.
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.
Additional technical information about the panel:
Brand: INNOLUX
Model: V400HJ6-PE1 Rev. C2
Type: a-Si TFT-LCD, CELL
Diagonal size: 40 inch
Resolution: 1920x1080, FHD
Display Mode: MVA, Normally Black, Transmissive
Active Area: 878.112x485.352 mm
Surface: Antiglare (Haze 1%)
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 6.0% (with Polarizer)
Contrast Ratio: 5000: 1
Display Colors: 16.7M (8-bit)
Response Time: 8.5 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V

 Brand: BBK, Model: 40LEX-5043 / FT2C.
Briefly from the TV: LCD, 39.5 ", 1920x1080, 1080p Full HD, DVR, sound: 16 W, 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 CV338H-U42 and LCD-panel V400HJ6-PE1. The power supply is combined with the MainBoard.
BBK 40LEX-5043 / FT2C LED TV with V400HJ6-PE1 LCD display, diagonal size 39.5 "(100 cm) in 16: 9 format. The required brightness of the screen is 250 cd / m² with LED backlight LED. The ratio of maximum brightness to minimum ( contrast ratio) is 5000: 1. The LED display is implemented in the model’s display manufacturing technology.The design and technical capabilities of the TV provide for watching broadcasts and films in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition according to the standard 1080p (Full HD).
40LEX-5043 / FT2C 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 x2, 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 911x567x212 mm, without stand 911x522x87 mm.
TV Weight: 6.5 kg.
Attention! The BBK 40LEX-5043 / FT2C LED TV panel V400HJ6-PE1 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.