LG LED
Model: 55LA620V
Chassis / Version: LD33B
Panel: LA62M55T120V12
LED backlight: LG lnnotek POLA2.0 55 L / R Type Rev0.1 0.1 2012.10.18
T-CON: 6870C-0421A
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX64905601 (1.7) LGP55-13PL2
MainBoard: EAX64797003 (1.2) EBR76823125 SAA36403538, SAA36403809
IC MainBoard: CPU: LGE2122, NAND: SAA36403538, H5TQ4G63AFR, H5TQ2G63AFR, NTP7513
Tuner: TSQ-G601D (B) EBL61240503
Control: IR: EBR77031901, Wi-Fi: EAT61813901 TWFM-B006D BEJTWFMB006D
Technical Specifications 55LA620V
LG 55LA620V
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 55LA620V does not turn on, the indicators on the front panel do not light up and do not blink. The TV does not respond to the control buttons and the remote control.
With such manifestations, a malfunction is most likely to be detected in the EAX64905601 power supply module. 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, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can test each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- 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 EAX64797003 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 replacement of CPU chips: LGE2122, NAND: SAA36403538, H5TQ4G63AFR, H5TQ2G63AFR, NTP7513 are carried out 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.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the tuner TSQ-G601D (B) EBL61240503 and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
It should be remembered! Attempts to independently repair the LG 55LA620V TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
Service manual / schematic diagram ------------> LG 55LA620V Chassis LD33B
The appearance of the MainBoard EAX64797003 is shown in the figure below:
EAX64797003
EAX64797003 can be used in TVs:
LG 42LA620V (Panel LC420DUE (SF)(U1)), LG 32LN570V (Panel LC320DUE (SF)(R1)), LG 50LA644V (Panel LC500EUN (SF)(F1)), LG 47LA660V (Panel LC470EUG (PF)(F1)), LG 47LA621V (Panel LC470DUE (SF)(U1)), LG 42LA644V (Panel LC420EUN (SF)(F2)), LG 39LA620V ZA (Panel T390HVJ01.0), LG 42LA621V ZD (Panel LC420DUE (SF)(U1)), LG 32LA621V ZD (Panel LC320DUE (SF)(U1)), LG 32LN655V (Panel LC320EUB (PF)(M1)), LG 42LA667V (Panel LC420EUH (PF)(P1) ), LG 47LN613V (Panel LC470DUE (SF)(R4)), LG 32LA667V ZB (Panel LC320EUB (PF)(P1)), LG 55LA660V ZA (Panel LC550EUH (PF)(P1)), LG 47LA620V ZA (Panel LC470DUE (SF)(U1)), LG 32LN613V ZB (Panel LC320DUE (SF)(R4)), LG 42LN655V ZB.BRUZLJU (Panel LC420EUH (PF)(M1)), LG 32LA644V ZA (Panel LC320EUN (SF)(F1)), LG 42LN613V (Panel LC420DUE (SF)(R4)), LG 47LA690V ZB (Panel LC47EUH (PF)(P1)), LG 47LA662V (Panel LC470EUG (PF)(F1)), LG 42LA645V 42LA645V-ZC.BRUYLJU (Panel LC420EUN (SF)(F3)), LG 32LA660V (Panel LC320EUB (PF)(P1)), LG 47LA644V 47LA644V-ZA (Panel LC470EUN (SF)(F2)), LG 50LA667S (Panel T500HVD02.1), LG 47LA691V (Panel LC470EUH (PF)(P1)), LG 32LA662V (Panel LC320EUB (PF)(P1)).
Main features of the device LG 55LA620V:
Installed matrix (LED-panel) LA62M55T120V12.
The matrix control uses the Timing Controller (T-CON) 6870C-0421A.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 55LA620V TV is carried out by the EAX64905601 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX64797003 module using CPU chips: LGE2122, NAND: SAA36403538, H5TQ4G63AFR, H5TQ2G63AFR, NTP7513 and others.
The tuner TSQ-G601D (B) EBL61240503 provides the reception of television programs and tuning to channels.