Technical description and composition of the BBK 28LEM-1001 TV, type of panel and applicable modules. The composition of the modules.BBK LED
Model: 28LEM-1001 / T2C
Chassis / Version: CV9202H-TPW
Panel: CX275DLEDM
LED driver (backlight): integrated into PSU
PWM LED driver: OB3350CP
Power Supply (PSU): CVB32005
PWM Power: PWM SOT23-6 AP3105NV
MainBoard: CV9202H-TPW
IC MainBoard: CPU: SPV9202BD (1416-D), DRAM: K4B1G1646G-BCKO, SPI FLASH: Winb25Q64FVSIG, AUDIO: TPA3110LD2
Tuner: ST03WS-2A-E
Specifications 28LEM-1001
BBK 28LEM-1001
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The BBK 28LEM-1001 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.
Most likely, in this case, the main switching power supply (UPS) CVB32005 is faulty. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually work normally in emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and less often the current sensor at the source of the key.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM SOT23-6 AP3105NV PWM controllers, in the absence of visible damage or frank short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
The faulty usually in these cases is the backlight matrix (LED-panel). More often the reason for this is the breakdown of the LEDs, or poor contact in the connectors of the strips, less often the LED driver may be malfunctioning.
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, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the CV9202H-TPW 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 attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: SPV9202BD (1416-D), DRAM: K4B1G1646G-BCKO, SPI FLASH: Winb25Q64FVSIG, AUDIO: TPA3110LD2 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).
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the tuner ST03WS-2A-E. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Owners of the 28LEM-1001 TV are advised to contact qualified personnel with the necessary work experience for repairs! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> BBK 28LEM-1001/T2C Chassis CV9202H-TPW
Service Manual with Schematic Diagram 47 pages of 2014 model 28LEM-1001/T2C, 28LEM-1007/T2C, 28LEM-1009/T2C, 32LEM-1001/T2C, 32LEM-1006/T2C, 40LEM-1006/FT2C, 42LEM-1009/FT2C, 42LEM-3070/FT2C
The appearance of the MainBoard CV9202H-TPW is shown in the figure below:CV9202H-TPW
CV9202H-TPW can be used in TVs:
AKAI LEA-39J29P (Panel HF390BGA-C1), BBK 32LEM-1001/T2C (Panel CX315DLEDM), DNS M39DM8 (Panel V390HJ1-P02 Rev C1), ERISSON 32LEE17 (Panel 720p HD 1366x768), FUSION FLTV-32T22 (Panel ST3151A05), FUSION FLTV-28T20 (Panel LCM-SM275TK301 (D0306)), FUSION FLTV-28T22 (Panel TH280L321-04), FUSION FLTV-32T23 (Panel ST3151A04-1 / Ver.2.4), FUSION FLTV-32T20 (Panel V320BK1-PS5 Rev.C7), TELEFUNKEN TF-LED40S28T2 (Panel CX400DLEDM), TELEFUNKEN TF-LED29S30T2 (Panel V290BJ1-XC01 CX290DLEDM), TELEFUNKEN TF-LED40S6T2 (Panel CX400DLEDM).
The appearance of the power supply
Main features of the BBK 28LEM-1001 device:
Installed matrix (LED-panel) CX275DLEDM.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the OB3350CP PWM controller.
The necessary supply voltages for all nodes of the TV BBK 28LEM-1001 are generated by the CVB32005 power module or its analogs using PWM SOT23-6 AP3105NV microcircuits.
MainBoard - the main board (motherboard) is a CV9202H-TPW module using CPU chips: SPV9202BD (1416-D), DRAM: K4B1G1646G-BCKO, SPI FLASH: Winb25Q64FVSIG, AUDIO: TPA3110LD2 and others.
The ST03WS-2A-E tuner provides TV reception and channel tuning.
BBK 28LEM-1001 LED TV with CX275DLEDM LCD, 28 "(71 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 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 for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC . Graphic I process and generate digital signals in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG. Stereo sound is realized by two built-in speakers. An audio processing system is used. NICAM STEREO.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI x2, USB x2. 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.
Overall dimensions: With stand 640x456x190 mm, Without stand 640x400x76 mm.
TV Weight: 4.8 kg.
Attention! The CX275DLEDM panel of the BBK 28LEM-1001 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.