Technical description and composition of the BBK LEM2961 TV, panel type and applicable modules. The composition of the modules.BBK LED
Model: LEM2961
Chassis / Version: 228-130726003
Panel: V290BJ1-PE1
T-CON: V290BJ1-XC01; CM1801B, CM501, CM601, P2003EV6, GT4128
LED driver (backlight): integrated into MainBoard
PWM LED driver: AP3039AM-G1, AP3608EM-G1
Trans LED driver: MSC ZY-T0134
Power Supply (PSU): integrated into MainBoard
PWM Power: SG6849 (PWM SOT23-6 AB3 ...)
MainBoard: MSTV2409-7C01-01
IC MainBoard: TPA3113D2, 25L3208E, PT2308-S, RT7257CM
Control: RC-LEM101
Technical Specifications LEM2961
BBK LEM2961
General repair guidelines for TV LCD LED
Possible malfunctions
- BBK LEM2961 does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
The malfunction in such cases, first of all, should be sought in the power elements of a switching power supply (IIP) - a network voltage converter (AC / DC), which in this TV model is combined with the MainBoard MSTV2409-7C01-01 main board. It is necessary to verify the presence of secondary voltages and, if not, check the power switches and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually 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. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM SG6849 (PWM SOT23-6 AB3 ...). It is checked only by replacement with a known good one.
- 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.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the 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 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 MSTV2409-7C01-01 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software). In cases of attempts to repair the MB board (SSB), it is necessary to check the health of its elements - AP3039AM-G1, AP3608EM-G1, TPA3113D2, 25L3208E, PT2308-S, RT7257CM which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
It should be remembered! Attempts to independently repair the BBK LEM2961 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!
To reduce the backlight current in LED drivers with the AP3039AM controller and the AP3608EM terminal stage (AP3039AM-G1 & AP3608EM-G1), the AP3608EM (AP3608E) microcircuit should proportionally increase the resistor from terminal 14 (ISET) to the housing. The maximum current in each channel (in milliamperes) for the Rset resistor (in kilo-ohms) is determined from the ratio 1.194V / Rset. In channels connected in parallel, the currents add up.
Main features of the BBK LEM2961 device:
Installed matrix (LED-panel) V290BJ1-PE1.
The matrix control uses the Timing Controller (T-CON) V290BJ1-XC01 ;.
To power the backlight LEDs, a converter is used, combined with the main board MSTV2409-7C01-01, controlled by the AP3039AM-G1, AP3608EM-G1 PWM controller. An LED driver is equipped with an MSC ZY-T0134 transformer.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter using SG6849 microcircuits (PWM SOT23-6 AB3 ...).
MainBoard - the main board (motherboard) is an MSTV2409-7C01-01 module, using TPA3113D2, 25L3208E, PT2308-S, RT7257CM, and others microcircuits.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V290BJ1-PE1
Type: a-Si TFT-LCD, CELL
Diagonal size: 29.0 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 631.092x354.816 mm
Surface: Antiglare (Haze 1%)
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 5.4% (with Polarizer)
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit)
Response Time: 9.5 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
BBK LEM2961 LED TV with V290BJ1-PE1 LCD, 29 "(74 cm) diagonal, 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 1000 : 1. This model uses Edge LED backlighting, high-quality HD viewing at 1366x768 pixels is possible in the 720p (HD Ready) standard for graphic decomposition. The input high-frequency or video signal can be processed in analogue systems PAL, SECAM, NTSC Graphic digital signal processing and generation takes place in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p Supported media 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, component, SCART, RGB, VGA, HDMI x2, 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.
The power consumed by the TV in the operating mode from the network is 60 watts.
Overall dimensions: With stand 666x448x200 mm, Without stand 666x408x50 mm.
TV Weight: 5.7 kg.
Attention! The BBK LEM2961 LED TV panel V290BJ1-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.