Wednesday 25 March 2020

REPAIR / SERVICING TV BBK LEM2449HD

Technical description and composition of the BBK LEM2449HD TV, panel type and applicable modules. The composition of the modules.
BBK LED
Model: LEM2449HD
Chassis / Version: 20111129
Panel: V236H1-LE5 Rev. C1
LED driver (backlight): TV2415-ZC02-01 (A) 303C2415061 KB-6160 E310726 CH-D
PWM LED driver: RT8566, RT8296AH (8),
MOSFET LED driver: AO4468 (8), B6010D (3)
Trans LED driver: 100
Power Supply (PSU): AD-LEM1949 12V 3A
MainBoard: MSTV3208-ZC01-01 & 228-111105003 MTC236-C02F
IC MainBoard: CPU: MST6E48RHS-LF-Z1, SPI FLASH: S25FL032K, AUDIO: YD1517
Tuner: F21WT-3BAR-E
Technical Specifications LEM2449HD
BBK LEM2449HD
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK LEM2449HD TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
In such cases, the fault should be sought first in the AD-LEM1949 power supply module. It is necessary to measure its secondary output voltage, 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.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. The PWM chip 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 the remote control. Or for a second, the image may appear immediately after switching on.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the motherboard 228-111105003 should begin by checking the stabilizers and power converters needed to power the microcircuit 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 serviceability of its elements - F4568 1084, YD1517, F4558 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).
If the TV works normally from external devices, but does not tune into television channels, the F21WT-3BAR-E tuner may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Owners and users of the BBK LEM2449HD TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!

FIRMWARE FOR SPI FLASH  ----------->   BBK LEM2449HD, Main: MSTV2407-ZC01-01, Panel: HM236WU8-100


 Service Manual with Schematic Diagram 39 pages 2012 on ------------>   LED1975, LED2275F, LED2475F, LEM1988, LEM2288F, LEM2488F, LEM2681F, LEM3281F, LEM2249HD, LEM2449HD, LEM2648SD, LEM3282


 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.


Repair MainBoard
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).
Main features of the BBK LEM2449HD device:
Installed matrix (LED panel) V236H1-LE5 Rev. C1.
The LED driver TV2415-ZC02-01 (A) is used to power the backlight LEDs, it is controlled by the PWM controller RT8566, RT8296AH (8) ,. A transformer 100 is installed in the LED driver converter. Keys of the type AO4468 (8), B6010D (3) are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the BBK LEM2449HD TV is carried out by the AD-LEM1949 power supply module, or its analogs.
MainBoard - the main board (motherboard) is an MSTV3208-ZC01-01 module, using CPU chips: MST6E48RHS-LF-Z1, SPI FLASH: S25FL032K, AUDIO: YD1517 and others.
The F21WT-3BAR-E tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V236H1-LE5
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.6 inch
Resolution: 1920x1080, FHD
Display Mode: TN, Normally White, Transmissive
Active Area: 521.28x293.22 mm
Surface: Antiglare (Haze 25%)
Brightness: 300 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 13S8P WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V