LG LED
Model: 28LB450U ZB
Chassis / Version: LD41A
Panel: 328041563 Kenmos
LED backlight: 37TM6275000001 LG INNOTEK 28INCH 4014PKG 56EA Rev0.2 120720
T-CON: MT3151A05-3-XC-1
LED driver (backlight): MT2751A01-1-P-5 CCP-518SW
Power Supply (PSU): Adapter + 19V 2.0A
MainBoard: EAX65377507 (1.0), EBR78623422
IC MainBoard: LGE2133, H27U1G8F2CTR, M24C256, MX25L8006EM2I, TAS5733
Tuner: TDJM-G101D
Specifications 28LB450U
LG 28LB450U
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 28LB450U does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to the remote control and control buttons.
In such cases, the main switching power supply, the Adapter, may be faulty.
The external adapter + 19V 2.0A power supply is not always subject to repair, especially since the owner can purchase it independently. But, in some cases, it makes sense to open it and eliminate the simple typical defects inherent in converters in pulsed sources.
If there is no 19V voltage at the output, it is necessary first of all to check the power switches and rectifier diodes for a possible breakdown.
In case of any breakdown of the diodes in the secondary circuits, the converter can operate in emergency short circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the main fuse and / or current sensor at the source of the key 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 controller chip (PWM) 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.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V for them. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX65377507 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing elements LGE2133, H27U1G8F2CTR, M24C256, MX25L8006EM2I, TAS5733 requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
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 TDJM-G101D tuner. 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.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
SCHEMATIC MANUAL ---------------------> LG CHASSIS: LA40A, LD41A MODEL: 28LB45** 28LB45**-Z*.
The appearance of the MainBoard EAX65377507 is shown in the figure below:EAX65377507
EAX65377507 can be used in TVs:
LG 28LB450U ZB (Panel 328041563 Kenmos), LG 24LB450U ZB (Panel V236BJ1-LE2 REV.C1), LG 24MT45V LG 24MT45V-PZ (Panel V236BJ1-LE2 Rev.C1), LG 24LB457U (Panel V236BJ1-LE2 Rev.C1), LG 22MT55V 22MT55V-PZ (Panel LM215WF3 (SL)(K1)), LG 22LB450U (Panel 1366x768 HD).
Main features of the device LG 28LB450U:
Installed matrix (LED-panel) 328041563 Kenmos.
The matrix control uses the Timing Controller (T-CON) MT3151A05-3-XC-1.
The LED driver MT2751A01-1-P-5 is used to power the backlight LEDs.
To power all the internal components of the LG 28LB450U TV, an external adapter + 19V 2.0A type source is used.
MainBoard - the main board (motherboard) is an EAX65377507 module, using chips LGE2133, H27U1G8F2CTR, M24C256, MX25L8006EM2I, TAS5733 and others.
The TDJM-G101D tuner provides television reception and channel tuning.