Technical description and composition of the BBK LEM2993 TV, panel type and applicable modules. The composition of the modules.BBK LED
Model: LEM2993
Chassis / Version: TP.MS3463S.PB801
Panel: SK29M21A 76XR-DSV290-PE1
T-CON: V290BJ1-XC01
LED driver (backlight): integrated into MainBoard
PWM LED driver: SN51DP
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: TP.MS3463S.PB801
IC MainBoard: MSD3463GU, GD25Q64, OB6220VP
Tuner: XF-3SDT-H
Technical Specifications LEM2993
BBK LEM2993
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The BBK LEM2993 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 such cases, the main power source - the AC / DC voltage converter, which is combined with the MainBoard TP.MS3463S.PB801 board, may turn out to be faulty. Then it is necessary to measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of power switches and rectifier diodes of the converters for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
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 SOT23-6 PWM chips are usually checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
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 TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the TP.MS3463S.PB801 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 microchips MSD3463GU, GD25Q64, OB6220VP 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 XF-3SDT-H tuner is established after checking the software and all the supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
It should be remembered! Attempts to independently repair the BBK LEM2993 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
FIRMWARE FOR SPI FLASH -----------> BBK LEM2993, Main: TP.MS3463S.PB801, Panel: SK29M21A
Service Manual with Schematic Diagram 32 pages on the model -----------> LEM1993, LED1994, LEM1995, LEM1996, LEM1997, LEM2293F, LED2294F, LEM2295F, LEM2296F, LEM2297F, LEM2493F, LED2494F, LEM2495F, LEM2496F, LEM2497F, LEM2993, LED2994, LEM2995, LEM2996, LEM2997, LED2253FW, LED1952DTG, LED2252FDTG, LED2452FDTG, LED2278F.
The appearance of MainBoard TP.MS3463S.PB801 is shown in the figure below:TP.MS3463S.PB801
TP.MS3463S.PB801 can be used in TVs:
AKAI LEA-40V35M (Panel LSC400HM06), AKIRA 32LED38T2P (Panel ST3151A05-8), AKIRA 32LED02T2M (Panel ST3151A04-9 Ver.2.1), BBK 32LEM-1029/TS2C (Panel C320X16-E18-H), BBK 39LEM-1033/TS2C (Panel C390X15-E8-A G01), BBK 32LEM-1026/TS2C (Panel CX315DLEDM ST3151A05-8), BBK 32LEM-1027/TS2C (Panel ST3151A05-8 / CX315DLEDM), DEXP F43C7100K (Panel LC430DUY (SH)(A1)), DEXP F42B7000M (Panel V420HJ2-P01), DEXP F43C7000C (Panel C430F14-E1-L / LC430DUY), DEXP F40B7100K (Panel LSC400HN02-G02 40N06-L-HPX1F1), DEXP H28C7100C (Panel C275X15-E1-H (G31)), DEXP H32C7300K (Panel LSC320AN02), DEXP H32D7100C (Panel ST3151A05-8 Ver2.5), DEXP H28D7300K (Panel HV280WX2-260), ERISSON 32LES78T2W (Panel KM0320LDRH0037), ERISSON 32LEE30T2 (Panel LK315T3HB87-12V), SUPRA STV-LC32T560WL (Panel LSC320AN10), SUPRA STV-LC32T550WL (Panel LSC320AN02), SUPRA STV-LC40T500WL (Panel C39X15-E7-A), TELEFUNKEN TF-LED32S45T2 (Panel LK315T3HB87-12V), THOMSON T39D20DH-01B (Panel T390XVN01.0).
Main features of the BBK LEM2993 device:
Installed matrix (LED panel) SK29M21A 76XR-DSV290-PE1.
The matrix control uses the Timing Controller (T-CON) V290BJ1-XC01.
To power the backlight LEDs, a converter is used, combined with the TP.MS3463S.PB801 main board, controlled by the SN51DP PWM controller.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a module TP.MS3463S.PB801, using microchips MSD3463GU, GD25Q64, OB6220VP and others.
The XF-3SDT-H tuner allows you to receive television programs and tune to channels.
BBK LEM2993 LED TV with SK29M21A LCD display, diagonal size 29 "(74 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) is 3000: 1 This model uses side illumination from Edge LEDs. You can view images in high quality HD at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM. Digital signal processing and generation takes place in the standards 480i, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats: MP3, WMA, MPEG4, MKV, JPEG. Stereo sound is realized by two built-in 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, audio x2, VGA, HDMI x3, USB. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768.
Overall dimensions: With a support of 670x443x175 mm, Without a support of 670x406x53 mm.
Attention! The SK29M21A panel of the BBK LEM2993 LED TV 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.
