Wednesday 25 March 2020

REPAIR / SERVICING TV BBK LEM2488FDT

Technical description and composition of the BBK LEM2488FDT TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: LEM2488FDT
Chassis / Version: S243P052YYNLA
Panel: LC230EUE // LM230WF5 (TL) (D1)
T-CON: LM230WF5-TLD1
LED driver (backlight): LDA15-63V240K // FSE060E0 L-CEM1
Power Supply (PSU): L-CEM1 FSE060E0
PWM Power: LD7535 (PWM 6 pin)
MainBoard: L0M05 (1) // 88XR-TL05022488FDT
IC MainBoard: MSD309PX-LF-SW, Spi Flash - 25Q32BVSIG
Tuner: R620D
Control: RC-LEM100, IR: 5800-D26E60-M000 Ver: 01.00
Technical Specifications LEM2488FDT
BBK LEM2488FDT
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The BBK LEM2488FDT TV does not turn on. There are no signs of operability. The indicators on the front panel do not shine and do not blink, and the remote control and control buttons do not respond.
In such cases, the fault should be sought first in the L-CEM1 power supply module. 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 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 supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. PWM chip LD7535 (PWM 6 pin) can also cause a malfunction of the power switch of the converter and is checked by replacement.
- 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.
Often in such cases, there is no 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 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.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the L0M05 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). Sometimes they require checking or replacing (if necessary) the elements of the MainBoard board - MSD309PX-LF-SW, Spi Flash - 25Q32BVSIG. In cases where the BGA processor is used, its malfunction is usually detected by local heating.
If you suspect a malfunction of the R620D tuner, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary voltage levels and impulses of data exchange with the processor via the I2C bus at the corresponding terminals of the tuner.
Attention to users! Independent repair of the BBK LEM2488FDT TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>   BBK LED1975, LED2275F, LED2475F, LEM1988, LEM2288F, LEM2488F (MST6M182VG + 2IN1 POWER SUPPLY)


FIRMWARE FOR SPI FLASH  ----------->   BBK LEM2488FDT L0M05(1) LC230EUE


 The appearance of the MainBoard L0M05 is shown in the figure below:
The MainBoard L0M05 uses the MSD309B processor, a BGA-based DDRAM random access memory (RAM) and an SPI Flash ROM of type 25Q32 (4Mb).
It is advisable to start the repair of the motherboard by checking the voltage converters and linear stabilizers necessary to provide power to the nodes in the operating and standby modes. The processor core is powered by + 1.5V. Also, the processor voltage requires + 2.5V and + 3.3V.
If the display backlight is working properly and there is no image, it is necessary to check the panel power (depending on the type, + 5V or + 12V), which is more convenient to measure directly on the LVDS connector. If, in the presence of all the supply voltages, the TV does not enter the operating mode, does not respond to the Remote Control and control buttons, you should update the SPI Flash firmware.
L0M05 can be used in TVs:
BBK LED1955DT (Panel V185B1-LE1 Rev.C1), BBK LED2275FDT (Panel V215H1-LE1 REV.C1), BBK LED2475FDT (Panel LC230EUE (TD)(A1)), BBK LEM1968DT Ver1 (Panel V185B1-LE1 Rev.C1), BBK LEM2488FDT (Panel LC230EUE), BBK LEM1988DT (Panel V185B1-LE1 Rev.C1 CMO), BBK LED2455FDT (Panel LC230EUE (TD)(A1)).
The appearance of the power supply
Main features of the BBK LEM2488FDT device:
Installed matrix (LED-panel) LC230EUE or LM230WF5 (TL) (D1).
The matrix control uses the Timing Controller (T-CON) LM230WF5-TLD1.
The LED driver LDA15-63V240K is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the BBK LEM2488FDT TV are generated by the L-CEM1 power module or its analogs using LD7535 microcircuits (PWM 6 pin).
MainBoard - the main board (motherboard) is an L0M05 module, using microchips MSD309PX-LF-SW, Spi Flash - 25Q32BVSIG and others.
The R620D tuner provides TV reception and channel tuning.
Information from an alternative source:
BBK LEM2488FDT
Panel Type (Matrix): LM230WF5 (TL) (D1)
Motherboard: L0M05 (02)
T-con: LM230WF5-TLD1 P / N: 6870S-1120A
LED Driver: OT2405-0, IR: 5800-D26E60-M000 Ver: 01.00
PSU: F782003311 FSE060E0
Remote control: RC-LEM100
Additional technical information about the panel:
Brand: LG Display
Model: LC230EUE-SEA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.0 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 509.184x286.416 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC)
Response Time: 5 (G to G)
Frequency: 60Hz
Lamp Type: 17S2P WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V