Wednesday, 25 March 2020

REPAIR / SERVICING TV BBK LEM3284DT2

Technical description and composition of the BBK LEM3284DT2 TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: LEM3284DT2
Chassis / Version: MSDV3222
Panel: LSC320AN02
LED backlight: CRH-P32CA3535T030751U-REV1.0
LED driver (backlight): with integrated MainBoard
PWM LED driver: AP3039AM-G1, AP3608EM
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: MSDV3222-ZC01-01 - MSAV3220-ZC26-02 (B) - 303C3220156
IC MainBoard: CPU: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300
Tuner: CY
Technical Specifications LEM3284DT2
BBK LEM3284DT2
General repair guidelines for TV LCD LED
If BBK LEM3284DT2 does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a malfunction of the power supply elements combined with MainBoard MSDV3222-ZC01-01. In some cases, only the processor power regulator may be faulty. When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and the electrolytic capacitors of the filters of the converter secondary rectifiers. In the event of a fuse breaking, the reason should be sought in the power semiconductor elements of the pulse converter of the main power supply. First of all, it is necessary to check the diodes of the rectifier bridge of the mains voltage and the power key (s) of the converter. The complete inoperability of the power supply unit can be caused by a short circuit in the power elements in the primary circuit, followed by an open fuse, or a short circuit in the loads.
In most cases, key breakdowns in switching power supplies (SMPS) do not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM PWM chip from the manufacturer.
Sometimes the BBK LEM3284DT2 TV does not have an image, but there is sound, or the image appears and immediately disappears. In this case, there is a possibility of a malfunction of the LED driver - power converter for the backlight LEDs of the LSC320AN02 panel, or an open circuit in the LED circuit is possible. In such cases, first of all, it is necessary to verify the operability of the electrolytic capacitors of the filter by the power of the backlight unit.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for an open circuit, as well as the reliability of the connections in the connectors and rations of the terminals.
To check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
If the motherboard MSDV3222-ZC01-01 - MSAV3220-ZC26-02 (B) - 303C3220156 is faulty, first of all it is necessary to check all the linear stabilizers and power converters of its chips, and also, if necessary, update the software (software). Sometimes you can check the health of MB only by replacement.
If it is not possible to replace the MB board (SSB), you need to check the health of its elements - CPU: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300. Defective components should be replaced.
Before replacing the CY tuner, if there is no tuning to the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via I2C
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair only to professionals with sufficient experience in the field of electronic equipment repair.

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    MYSTERY MTV-3224LT2 Chassis MSDV3222-ZC01-01 (MSDV3222-YL01-01)

 Schematic Diagrams 10 pages of 2013 on the LEM2484DT2, LEM2484FDT2, LEM3284DT2, LED-32E58T.

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.


The appearance of the MainBoard MSDV3222-ZC01-01 is shown in the figure below:
The motherboard MSDV3222-ZC01-01 is made on a single chassis with a power module and an inverter to power the LED panel. The MSD308BT-SW multi-function control processor with built-in scaler is used. Repair of the power module is carried out according to standard technology - verification of power cells, electrolytic capacitors and secondary supply voltages. The following is a functional check of stabilizers and converters for powering the internal nodes of the processor and LCD panel. It should be borne in mind that if there are problems with the software in the SPI Flash chips manufactured by WINBOND, it is advisable to replace the chip itself with the contents of the software.
MSDV3222-ZC01-01 can be used in TVs:
BBK LEM3284DT2 (Panel LSC320AN02), MYSTERY MTV-2229LT2 (Panel M215HTN01.1 ), MYSTERY MTV-2429LT2 (Panel M240HTN01.2), MYSTERY MTV-2223LT2 (Panel LC215DTBA), MYSTERY MTV-2431LT2 (Panel V236BJ1 600), MYSTERY MTV-1924LT2 (Panel HT185WXF-100), MYSTERY MTV-3228LT2 (Panel LK315T3HB94), MYSTERY MTV-3023LT2 (Panel MT3151A05), MYSTERY MTV-2228LT2 (Panel RUNTK0001ZDP2), MYSTERY MTV-1929LT2 (Panel V185BJ1-PE1), MYSTERY MTV-3223LT2 (Panel LC315TU3A), MYSTERY MTV-3224LT2 (Panel HV320WX2-20A), MYSTERY MTV-3028LT2 (Panel ST2751A01-3), MYSTERY MTV-2428LT2 (Panel V236BJ1-P01), MYSTERY MTV-2424LT2 (Panel HM236WU8-200 ), MYSTERY MTV-4030LT2 (Panel V400HJ6-PE1), MYSTERY MTV-3031LT2 (Panel V290BJ1-PE1), MYSTERY MTV-3226LT2 (Panel V320BJ7-PE1).
Main features of the BBK LEM3284DT2 device:
Installed matrix (LED panel) LSC320AN02.
To power the backlight LEDs, a converter is used, combined with the main board MSDV3222-ZC01-01, it is controlled by the AP3039AM-G1, AP3608EM PWM controller.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is an MSDV3222-ZC01-01 module, using CPU chips: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300 and others.
The CY tuner allows you to receive television programs and tune to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LSC320AN02-0
Type: a-Si TFT-LCD, CELL
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: PVA, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare (Haze 2%), Hard coating (2H)
Glass Depth: 0.70 + 0.70 mm
Transmissivity: 6.5% (with Polarizer)
Contrast Ratio: 5000: 1
Display Colors: 16.7M (8-bit), CIE1931 69%
Response Time: 20 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V