Sunday 22 March 2020

REPAIR / SERVICING TV BBK 24LEM-5093

Technical description and composition of the TV BBK 24LEM-5093, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: 24LEM-5093 / FT2C
Chassis / Version: E309B-Y2-F0
Panel: LC230EUE SEA1
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3251
MOSFET LED driver: ME15N10
Power Supply (PSU): integrated into MainBoard
PWM Power: L7535
MOSFET Power: FS4N60F
MainBoard: E309B-Y2-F0 3CJ2856
IC MainBoard: MSD309BT, BIT3251 (8), RT7237AN (8), MSB101A. Win 25Q64FVSIG (8)
Tuner: TDA18273
Technical Specifications 49LEX-5048 / FT2C
BBK 24LEM-5093
General repair guidelines for TV LCD LED
Possible malfunctions
- BBK 24LEM-5093 does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons.
The malfunction in such cases should first be sought in the power elements of a switching power supply (IIP) - a network voltage converter (AC / DC), which in this TV model is combined with the MainBoard E309B-Y2-F0 main board. 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.
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. 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 commands from the remote control. Or the image appears immediately after turning on and disappears.
Often in such cases, there is no LED backlight. 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.
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, sometimes you can 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 turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the E309B-Y2-F0 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 chip replacement BIT3251 (8), RT7237AN (8), MSB101A. Win 25Q64FVSIG (8) are produced 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.
Owners and users of the BBK 24LEM-5093 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!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    BBK Chassis E309B-Y2-F0


 The appearance of the MainBoard E309B-Y2-F0 is shown in the figure below:
E309B-Y2-F0
E309B-Y2-F0 can be used in TVs:
BBK 24LEM-5093/FT2C (Panel LC230EUE SEA1), BBK 32LEM-3002/T2C (Panel SK32M32H).
Main features of the BBK 24LEM-5093 device:
Installed matrix (LED panel) LC230EUE SEA1.
To power the backlight LEDs, a converter is used, combined with the main board E309B-Y2-F0, controlled by a BIT3251 PWM controller. As the power elements of the LED driver, keys of the type ME15N10 are used.
The power module is combined with the MainBoard and is made according to the scheme of the flyback AC / DC voltage converter using L7535 microcircuits and power switches of the FS4N60F type.
MainBoard - the main board (motherboard) is an E309B-Y2-F0 module, using microchips MSD309BT, BIT3251 (8), RT7237AN (8), MSB101A. Win 25Q64FVSIG (8) and others.
The TDA18273 tuner provides television reception and channel tuning.
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