Technical description and composition of the LG 50LA620V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 50LA620V ZA
Chassis / Version: LD33B
Panel: LC500DUE (SF) (U1)
LED backlight: 6916L-1272A, 6916L-1273A, 6916L-1276A, 6916L-1241A
T-CON: LC500DUE-SFR1_Control_Merge 6870C-0452A; LG5831
LED driver (backlight): integrated into PSU; 93.2 ~ 118.5V 0.4A
PWM LED driver: BD9483F
MOSFET LED driver: MDD7N25, FDT86106
Power Supply (PSU): EAX64905501 (2.3) - LGP4750-13PL2 EAY62810801
PWM Power: SSC9527S (PWM Resonant), R2A20133D (PFC), ICE3BR4765JZ (Standby)
MOSFET Power: 13NM60N
MainBoard: EAX64797004 (1.1)
IC MainBoard: LGE2122 1402-BTAN, NAND: 3DAI8 JW857, H5TQ4G63AFR
Tuner: TDSQ-G601D (B) EBL61240503
Control: WIFI: TWFM-B006D
Specifications 50LA620V
LG 50LA620V
General repair guidelines for TV LCD LED
Failures of the EAX64905501 power module (2.3) can be expressed in different ways, for example, the LG 50LA620V does not turn on at all and the control lights on its front panel do not light up and do not blink, and there are no signs of operability. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is broken in the power supply, in most cases a breakdown of the power key (s) 13NM60N is detected, which can be integrated with the PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
The breakdown of the power switch of the pulse converter is often triggered by other elements, for example, in the stabilization or control circuits of this switch, as well as by the damper elements in its drain and TPI winding.
If the LG 50LA620V does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the backlight circuits of the LC500DUE (SF) (U1) panel is likely. LEDs or their power converter - LED driver may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the backlight assembly.
To check the health of the LEDs and contact connections in their power circuit, the panel must be disassembled.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
Repair of the EAX64797004 (1.1) motherboard should begin with the diagnosis and verification of all linear stabilizers and power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
In some cases, it is necessary to check or replace (if necessary) the elements of the MB board (SSB) - LGE2122 1402-BTAN, NAND: 3DAI8 JW857, H5TQ4G63AFR. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
The failure of the TDSQ-G601D (B) EBL61240503 tuner is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Attention! For users and owners of 50LA620V TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.
You can reduce the backlight current in TVs with LGP4750-13PL2 power supplies (EAX64905501) as follows. Current sensors in the R811-R818 LEDs - channel 1 and R829-R836 - channel 2. Resistors in the channels in pairs of 4.3 + 3.9 Ohm. You can reduce the backlight current by 25% by removing one pair of resistors in each channel.
SCHEMATIC manual -------------------> LG 50LA62XX 50LA6208 50LA620S 50LA620V (CHASSIS LD33B) .
SCHEMATIC manual -------------------> LGP4750-13PL2 EAX64905501 EAY62810801 power supply
The appearance of the MainBoard EAX64797004 is shown in the figure below:EAX64797004
EAX64797004 can be used in TVs:
LG 42LA660S ZA 42LA660V (Panel LC420EUH (PF)(P1) 120 Hz), LG 32LA620V (Panel LC320DUE (SF)(U1)), LG 42LN570V (Panel LC420DUE (SF)(R3)), LG 50LA620V ZA (Panel LC500DUE (SF)(U1)), LG 32LN575S (Panel LC320DUE (SF)(R1)), LG 42LA669V 42LA669V-ZE.BRUZLJU (Panel LC420EUH (PF)(P1)).
PSU Advanced
The 50LA620V model uses the EAX64905501 power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, it is a boost converter based on the R2A20133D PWM controller, which eliminates the charge current of the electrolytic capacitor of the rectifier filter directly from the network through open diodes, when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
The appearance of the power supply
Main features of the device LG 50LA620V:
Installed matrix (LED-panel) LC500DUE (SF) (U1).
The matrix control uses the Timing Controller (T-CON) LC500DUE-SFR1_Control_Merge.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the BD9483F PWM controller. As power elements of the LED driver, keys of the type MDD7N25, FDT86106 are used.
The necessary supply voltages for all nodes of the LG 50LA620V TV are generated by the EAX64905501 power supply module or its analogs using SSC9527S (PWM Resonant), R2A20133D (PFC), ICE3BR4765JZ (Standby) microcircuits and 13NM60N power switches.
MainBoard - the main board (motherboard) is an EAX64797004 module using LGE2122 1402-BTAN chips, NAND: 3DAI8 JW857, H5TQ4G63AFR and others.
Tuner TDSQ-G601D (B) EBL61240503 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC500DUE-SFU1
Type: a-Si TFT-LCD, Panel
Diagonal size: 50 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 1095.84x616.41 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 300 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: 2 strings WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
