Technical description and composition of the LG 42UB820V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42UB820V 42UB820V-ZH.ARUWLJU
Chassis / Version: LD48V
Panel: LC420EQE (PG) (M1)
LED backlight: 6922L-0130A, L-Type 6920L-0001C 6916L-1835A, R-Type 6920L-0001C 6916L-1836A
T-CON: 6870C-0502C, 6870S-1824A, LL405804, LL405807 V14 TM120 UHD Ver0.6
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX65727601 (1.7) EAY63250101 REV1.0 LGP42-14UL6
PWM Power: ICE3BR4765J
MainBoard: EAX66085703 (1.0) EBT6317450 // EAX66085704 EBT63174507
IC MainBoard: LGE7411 / LGE4331B4, 25L320BE, AT24C256C, H5TQ4G63AFR, NTP7514
Tuner: TDJM-G251D
Specifications 42UB820V
LG 42UB820V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 42UB820V TV does not turn on, does not respond to the remote control and buttons on the control panel, the indicators do not light or flash.
In such cases, the fault should be sought first in the EAX65727601 power supply module. Then it is necessary to measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of power switches and rectifier diodes of the converters for a possible short circuit.
In case of breakdowns of 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 mains fuse and / or current sensor at the source of the key 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) ICE3BR4765J, 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 the remote control. Or for a second, the image may appear immediately after switching on.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. The reason can be both in the power of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
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, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX66085703 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 LGE7411 / LGE4331B4, 25L320BE, AT24C256C, H5TQ4G63AFR, NTP7514 microcircuits 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.
Before replacing the TDJM-G251D 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
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 DIAGRAM -----------> LG 42UB820V, 42UB820V-ZH, 42UB828V, 42UB828V-ZH; Chassis LD48V
The appearance of the MainBoard EAX66085703 is shown in the figure below:EAX66085703
EAX66085703 can be used in TVs:
LG 42UB820V 42UB820V-ZH.ARUWLJU (Panel LC420EQE (PG)(M1)), LG 49UB830V (Panel LC490EQE (XG)(F2)), LG 49UB820V 49UB820V-ZH (Panel LC490EQE (XG)(F2) ), LG 40UB800V 40UB800V-ZA (Panel V400DK1-KE1).
The appearance of the power supply
Main features of the device LG 42UB820V:
Installed matrix (LED-panel) LC420EQE (PG) (M1).
The matrix control uses the Timing Controller (T-CON) 6870C-0502C.
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages are generated for all nodes of the LG 42UB820V TV by the EAX65727601 power module, or its analogs using ICE3BR4765J microcircuits.
MainBoard - the main board (motherboard) is an EAX66085703 module, using chips LGE7411 / LGE4331B4, 25L320BE, AT24C256C, H5TQ4G63AFR, NTP7514 and others.
The TDJM-G251D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EQE-PGM1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 3840x2160, UHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 400 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + Dithering), CIE1931 72%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: V-by-One 8 lane, 51 pins
Voltage: 12.0V