Technical description and composition of the LG 22LB450U TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 22LB450U
Chassis / Version: MT55 / LD41A
Panel: 1366x768 HD
LED backlight: EDGE LED
LED driver (backlight): integrated into MainBoard
PWM LED driver: DT1641S
MOSFET LED driver: SMK630D
Power Supply (PSU): Adapter 19V
MainBoard: EAX65377507 (1.0)
IC MainBoard: LGE2134, AT24C256C, MX25L8006E, H27U1G8F2CTR-BC, BA7657F, TAS5733
Tuner: TDJM-G101D
Technical Specifications 22LB450U
LG 22LB450U
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 22LB450U TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
In such cases, the adapter power supply is usually faulty.
The owner of the TV can purchase an external power supply unit such as Adapter and repairing it is not always advisable. In any case, the simplest typical defects characteristic of most IIP schemes can be easily detected and eliminated after opening. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches and rectifier diodes of the converters for a probable 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.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- 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 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). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - LGE2134, AT24C256C, MX25L8006E, H27U1G8F2CTR-BC, BA7657F, TAS5733 and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
Before replacing the TDJM-G101D tuner, if there is no tuning for 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 the I2C bus
We recommend the owners of the 22LB450U TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
FIRMWARE FOR SPI FLASH --> LG 22LB450U MT55/LD41A, Main: EAX65377507 (1.0), Panel: 1366x768 HD.
Service manual and schematic diagram----------------> LG 22LB450U Chassis LD41A.
To reduce the backlight current in LED drivers with the DT1641AS controller (DT1641S), you can increase the total resistance of the resistors from pin 7 (RISET) to the chassis. The exact proportional dependence may not be observed if there is additional control on this input, then the ratings should be selected empirically !!
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 22LB450U:
Installed matrix (LED-panel) 1366x768 HD.
To power the backlight LEDs, a converter is used, combined with the main board EAX65377507, controlled by the DT1641S PWM controller. As power elements of the LED driver, keys of the SMK630D type are used.
To power all the internal components of the LG 22LB450U TV, an external adapter 19V type source is used.
MainBoard - the main board (motherboard) is an EAX65377507 module, using chips LGE2134, AT24C256C, MX25L8006E, H27U1G8F2CTR-BC, BA7657F, TAS5733 and others.
The TDJM-G101D tuner provides television reception and channel tuning.