Technical description and composition of the BBK LEM2648SD TV, panel type and applicable modules. The composition of the modules.BBK LED
Model: LEM2648SD
Panel: V260B1-LE9 revC1
LED driver (backlight): TV2631-ZC02-01
PWM LED driver: RT8566
MOSFET LED driver: B0610D
Power Supply (PSU): TV2632-ZC02-02
PWM Power: OB2263 (PWM SOT23-6)
MainBoard: MSTV3208-ZC01-01
IC MainBoard: CPU: MST6M48RHS-LF-Z1; SPI Flash: 25Q32; Sound: TDA1517P
Tuner: F21WT-3BAR-E
Technical Specifications LEM2648SD
BBK LEM2648SD
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The BBK LEM2648SD TV does not turn on at all. There is no reaction to the remote control or to the control buttons from the front panel. Indicator lights do not light or flash.
Failure in such cases should be sought in the TV2632-ZC02-02 power supply circuits. 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 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 (PWM) OB2263 (PWM SOT23-6). It is checked only by replacement with a known good one.
- 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.
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. 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 indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the MSTV3208-ZC01-01 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 CPU chips: MST6M48RHS-LF-Z1; SPI Flash: 25Q32; Sound: TDA1517P are manufactured 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.
Before changing the F21WT-3BAR-E tuner, if it is not possible to tune to television channels, 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
Once again, remind users! Attempts to self-repair a BBK LEM2648SD TV without the appropriate qualifications and the necessary experience can lead to its complete failure to repair!
To reduce the backlight current in LED drivers with an RT8566 controller, it is necessary to proportionally increase the resistance of the resistor from terminal 2 (RISET) to the housing. The current in each channel is determined from the 543.6 / Rset ratio.
Service Manual with Schematic Diagram 39 pages 2012 on -----------> LED1975, LED2275F, LED2475F, LEM1988, LEM2288F, LEM2488F, LEM2681F, LEM3281F, LEM2249HD, LEM2449HD, LEM2648SD, LEM3282.
The appearance of the MainBoard MSTV3208-ZC01-01 is shown in the figure below:The motherboard MSTV3208-ZC01-01 is made using the multifunction microprocessor MST6M48RHS-LF, which includes a scaler (graphic controller-scaler). To organize the work of the processor, the external RAM H5PS5162GFR 512Mb DDR2 SDRAM in BGA version and SPI FLASH 25Q32 (4Mb) are used. To provide power to the processor core, a DC / DC converter with an output voltage of 1.2V is used, assembled on the basis of the MP1482 PWM controller. Other nodes of the processor are powered by linear voltage stabilizers 2.5V, 3.3V. 1.8V voltage is used to power the DDR RAM, 3.3V is needed for the SPI FLASH ROM.
It is advisable to start the MainBoard repair by checking the supply voltage in Stand-by mode 5V and 3.3V. In operating mode, check the operation of all linear stabilizers and the DC / DC converter. If there is a backlight and there is no image, you need to check the power of the 5V or 12V panel (depending on the type of LCD panel), which should be present directly on the LVDS connector.
If the indicator signals Stand-by mode and does not respond to the remote control and control buttons, it is recommended to update the SPI Flash software. Taking into account the glitchiness of Winbond SPI chips, it is advisable to replace them with new ones in case of software failures.
MSTV3208-ZC01-01 can be used in TVs:
BBK LEM2648SD (Panel V260B1-LE9 revC1), BBK LEM3248SD (Panel HV320WX2-130 (B3)), BBK LMP3229HDU Ver1 (Panel T315HW02 v.7), BBK LMP3229HDU Ver2 (Panel T315HW04 V7), BBK LEM2649HD (Panel V260H1-LE7 Rev C1), MYSTERY MTV-2607W (Panel V260H1-L05), MYSTERY MTV-3206 (Panel T315XW04 V.7), MYSTERY MTV-3207W (Panel V315B3-L04 rev.c1), MYSTERY MTV-3213LW (Panel T315XW04 V.8), MYSTERY MTV-2220LW (Panel CLAA215FA15), MYSTERY MTV-3207W (Panel HV320WX2-110), MYSTERY MTV-2614LW (Panel V260H1-LE6), MYSTERY MTV-3208WH (Panel V315H1-L02), MYSTERY MTV-2411LW (Panel V236H1-LE5 Rev.C1), MYSTERY MTV-2618LW (Panel V260B2-LE11), MYSTERY MTV-2211LW (Panel CLAA215FA10), MYSTERY MTV-2414LW (Panel V236H1-L01), MYSTERY MTV-2611LW (Panel V260H1-LE6 Rev.C1), MYSTERY MTV-3206W (Panel T315XW03 V.3), MYSTERY MTV-3211LW (Panel V315H3-LE2 Rev. C1), MYSTERY MTV-4207WH (Panel T420HW09 V.1), MYSTERY MTV-1921LD (Panel HT185WX3).
The appearance of the power supply
Main features of the BBK LEM2648SD device:
Installed matrix (LED-panel) V260B1-LE9 revC1.
To power the backlight LEDs, the TV2631-ZC02-01 LED driver is used, controlled by the RT8566 PWM controller. As the power elements of the LED driver, keys of the type B0610D are used.
The necessary supply voltages for all nodes of the TV BBK LEM2648SD are generated by the TV2632-ZC02-02 power module, or its analogs using OB2263 chips (PWM SOT23-6).
MainBoard - the main board (motherboard) is an MSTV3208-ZC01-01 module, using CPU chips: MST6M48RHS-LF-Z1; SPI Flash: 25Q32; Sound: TDA1517P and others.
The F21WT-3BAR-E tuner provides television reception and channel tuning.
BBK LEM2648SD LED TV with V260B1-LE9 LCD, 26 "(66 cm) diagonal size of 16: 9 format. The required screen brightness of 350 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 800 : 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 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.
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, 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.
The power consumed by the TV in the operating mode from the network is 55 watts.
Overall dimensions: With stand 640x466x180 mm, Without stand 640x421x40 mm.
TV mass: 6 kg.
Attention! The BBK LEM2648SD LED TV panel V260B1-LE9 revC1 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.