Technical description and composition of the BBK LEM1949SD TV, panel type and applicable modules. The composition of the modules.BBK LED
Model: LEM1949SD
Chassis / Version: ver1 228-120417003
Panel: HT185WX3-100
LED driver (backlight): KB-6160 TV2414-ZC02-01
PWM LED driver: RT8296AH (8), BIT3251 (8),
MOSFET LED driver: AO4438 (8), AO 4468 (8), AO4435 (8)
Power Supply (PSU): AD-LEM1949 12v 3a
MainBoard: MTC185LED 222-110704005 // 20111203-Ver01 E5B1 228111105001-LED-MTC185
IC MainBoard: TDA1517P (18), F4558 (8), X50V330 (16), 1119GG, MP1482DS (8).
Control: RC3229
Technical Specifications LEM1949SD
BBK LEM1949SD
General repair guidelines for TV LCD LED
Possible malfunctions
- BBK LEM1949SD 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.
Most likely in this case, the main switching power supply (IIP) AD-LEM1949 is faulty. It is necessary to measure its secondary output voltages, and in case of their absence, check the serviceability of the power switches of the 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.
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 the excess of maximum current or voltage values. 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 (PWM). It is checked only by replacement with a known good one.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
In such cases, the most likely malfunction of the LED backlight elements. 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.
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 TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the MTC185LED 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). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements TDA1517P (18), F4558 (8), X50V330 (16), 1119GG, MP1482DS (8). Faults in BGA chips are usually easy to detect by heating.
Attention to users! Self-repair of the TV BBK LEM1949SD without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
Main features of the BBK LEM1949SD device:
Installed matrix (LED panel) HT185WX3-100.
To power the backlight LEDs, the KB-6160 LED driver is used, controlled by the PWM controller RT8296AH (8), BIT3251 (8) ,. As the power elements of the LED driver, keys of the type AO4438 (8), AO 4468 (8), AO4435 (8) are used.
The formation of the necessary supply voltages for all nodes of the TV BBK LEM1949SD is carried out by the power module AD-LEM1949, or its analogues.
MainBoard - the main board (motherboard) is an MTC185LED module, using TDA1517P (18), F4558 (8), X50V330 (16), 1119GG, MP1482DS (8) microcircuits. and others.
BBK LEM1949SD LED TV with HT185WX3-100 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. The LED display backlighting technology is implemented in the model’s display technology. High quality HD images can be viewed 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 analogue systems PAL, SECAM, NTSC: Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MKV, JPEG.
The power of the sound system 3 W (2x1.5 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, component, SCART, RGB, VGA, HDMI x2, USB. 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, 1360x768.
Overall dimensions: With stand 458x350x98 mm, Without stand 458x310x38 mm.
The mass of the TV: 2.4 kg.
Attention! The BB18 LEM1949SD LED TV panel HT185WX3-100 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.
