Technical description and composition of the BBK LED1955DT TV, type of panel and applicable modules. The composition of the modules.BBK LED
Model: LED1955DT
Panel: V185B1-LE1 Rev. C1
LED driver (backlight): LDA15-42V160H
PWM LED driver: BIT3251 (8)
MOSFET LED driver: B6010D (3)
Power Supply (PSU): L-CEM1 FSE040A REV: 1.3
PWM Power: LD7535 (PWM 6 pin)
MOSFET Power: SVD4N55F, STPS20LCD100C
MainBoard: L0M05 (00) 1108H1157 88XR-SKD1955DT
IC MainBoard: YD1517P (18), MP1484EN (8)
Control: RC2252
Technical Specifications LED1955DT
BBK LED1955DT
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The BBK LED1955DT TV does not turn on, does not respond to the remote control and the control panel buttons, does not blink with any indicators.
With such manifestations, a malfunction is likely to be detected in the L-CEM1 power supply module. It is necessary to measure its secondary output voltages, and in case of their absence, check the serviceability of power switches (SVD4N55F, STPS20LCD100C) of converters 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 a short circuit in the 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, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. PWM chip LD7535 (PWM 6 pin) can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
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, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the L0M05 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). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its YD1517P (18), MP1484EN (8) chips and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
Attention to users! Self-repair of the BBK LED1955DT TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> BBK LED1955DT, LED2255FDT, LED2455FDT (MSD309)
Service Manual with Schematic Diagram 82 pages of 2011 on the model LED1955DT, LED2255FDT, LED2455FDT.
The appearance of the MainBoard L0M05 is shown in the figure below:The MainBoard L0M05 uses the MSD309B processor, a BGA-based DDRAM random access memory (RAM) and an SPI Flash ROM of type 25Q32 (4Mb).
It is advisable to start the repair of the motherboard by checking the voltage converters and linear stabilizers necessary to provide power to the nodes in the operating and standby modes. The processor core is powered by + 1.5V. Also, the processor voltage requires + 2.5V and + 3.3V.
If the display backlight is working properly and there is no image, it is necessary to check the panel power (depending on the type, + 5V or + 12V), which is more convenient to measure directly on the LVDS connector. If, in the presence of all the supply voltages, the TV does not enter the operating mode, does not respond to the Remote Control and control buttons, you should update the SPI Flash firmware.
L0M05 can be used in TVs:
BBK LED1955DT (Panel V185B1-LE1 Rev.C1), BBK LED2275FDT (Panel V215H1-LE1 REV.C1), BBK LED2475FDT (Panel LC230EUE (TD)(A1)), BBK LEM1968DT Ver1 (Panel V185B1-LE1 Rev.C1), BBK LEM2488FDT (Panel LC230EUE), BBK LEM1988DT (Panel V185B1-LE1 Rev.C1 CMO), BBK LED2455FDT (Panel LC230EUE (TD)(A1)).
The appearance of the power supply
Main features of the BBK LED1955DT device:
Installed matrix (LED-panel) V185B1-LE1 Rev.C1.
The LED driver LDA15-42V160H is used to power the backlight LEDs, it is controlled by the BIT3251 PWM controller (8). As power elements of the LED driver, keys of the type B6010D (3) are used.
The necessary supply voltages for all nodes of the TV BBK LED1955DT are generated by the L-CEM1 power module or its analogs using LD7535 microcircuits (PWM 6 pin) and power switches of the SVD4N55F, STPS20LCD100C type.
MainBoard - the main board (motherboard) is an L0M05 module, using YD1517P (18), MP1484EN (8) microcircuits, and others.
Additional technical information about the panel:
Brand: CMO
Model: V185B1-LE1
Type: a-Si TFT-LCD, Panel
Diagonal size: 18.5 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 409.8x230.4 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (8-bit), CIE1931 70%
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 13S8P WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V
BBK LED1955DT LED TV with V185B1-LE1 LCD display, 19 "(48 cm) diagonal size in 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 1000 : 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 for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC . Graphic processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p Supported multimedia file formats:. MP3, WMA, MPEG4, MKV, VideoCD, SVCD, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide 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, audio x2, 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 digital tuner is capable of receiving television channels in DVB-T MPEG4 standards.
The power consumed by the TV in the operating mode from the network is 30 watts.
Overall dimensions: 470x341x150 mm.
TV Weight: 3.5 kg.
Attention! The BBK LED1955DT V185B1-LE1 Rev.C1 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.
