Friday, 28 February 2020

REPAIR / SERVICING TV LG 42LV3500

Technical description and composition of the LG 42LV3500 TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LV3500
Panel: LC420EUN (SD) (V3) // T420HW08 V.1
LED backlight: 3660L-0374A 201, 42 V6 Edge FHD-3 Rev1.0 1 L-Type / R-Type
T-CON: 6870C-0368A V6 32-42-47 FHD TM120HZ_TFTRA
LED driver (backlight): 3PEGC20008B-R PCLF-D002B Rev1.0 6917L-0061B
Power Supply (PSU): EAX63729001 / 7
PWM Power: FAN7930B (PFC), 3BR4765JZ (Standby DIP-7), L6599AD (PWM Resonant)
MOSFET Power: K10A60D
MainBoard: EAX64290501 (0) EBR74015318
IC MainBoard: CPU: LGE107DC-RP, DDR: H5TQ1G63DFR-PBC, NAND: 01GW3B2CN6E, SPI FLASH: 25Q80BVSIG
Tuner: TDTJ-S001D
Control: IR: 1BF-3001A
Specifications 42LV3500
LG 42LV3500
General repair guidelines for TV LCD LED
Repair of the LG 42LV3500 ZA TV should begin with a careful external inspection of all its components and modules. According to some external signs of a change in the state of some elements, it is sometimes possible to make assumptions about the nature of the defect, as well as determine the further direction of the troubleshooting. Ring cracks in the soldering of the leads of the heating elements, swollen electrolytic capacitors, a charred paint layer on the resistors - all this for the repairman can be a significant clue in the assumptions about the causes and consequences of the malfunction.
If the TV does not turn on, no control lights are on or blinking, there are no sounds when you turn on, and there is not the slightest sign of operability - the most likely malfunction is in the power module. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. When it is broken, the power elements of transistors and rectifier bridge diodes should be checked for avalanche (thermal) breakdown.
If the power keys of the pulse converter are not equal, you should pay attention to other elements in their bundling, which may be the result or cause of their breakdown.
In cases where the LG 42LV3500 TV has lost an image, and the sound is there and all the other functions are operational, there is a possibility of a malfunction of the LED driver (a converter for powering the T420HW08 V.1 backlight LEDs). When you turn on the TV, the image may appear briefly and disappear immediately. It must be borne in mind that with such manifestations the LEDs themselves also fail.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for an open circuit, as well as the reliability of the connections in the connectors and rations of the terminals.
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.
Repair or diagnostics of the EAX64290501 (0) motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, you should update the software (software).
In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: LGE107DC-RP, DDR: H5TQ1G63DFR-PBC, NAND: 01GW3B2CN6E, SPI FLASH: 25Q80BVSIG and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If a TDTJ-S001D tuner is suspected of malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary voltage levels at the corresponding terminals of the tuner.
Once again, remind users! Attempts to self-repair the LG 42LV3500 TV without the appropriate qualifications and experience can lead to its complete non-repairability!



 SCHEMATIC DIAGRAM ---------->  LG 42LV3500 42LV3520 Chassis LA01U



 The appearance of the MainBoard EAX64290501 is shown in the figure below:
EAX64290501
EAX64290501 can be used in TVs:
LG 32LV2500-ZA (Panel T315XW06 V.3), LG 37LV3500-ZA (Panel T370HW05 V.1), LG 42LV3400-ZA (Panel T420HW08 V.1), LG 32LK530 (Panel LC320WUD (SC)(A3)), LG 37LK430 (Panel LC370WUE), LG 32LK451 ZA (Panel T315HW04 V.9), LG 42LV3551 (Panel LC420EUN (SD) (V3)), LG 47LW4500 (Panel LC470EUF (SD)(F2)), LG 32LK551 ZB (Panel LC320WUD (SC)(A2)), LG 42LV3500 (Panel LC420EUN (SD)(V3)), LG 42LK551 ZB (Panel V420H2-LH5), LG 42LK451 42LK451-ZG.BRUYLJU (Panel T420HW09 V0), LG 42LK530 (Panel LC420WUF (SC)(A2)), LG 47LK950 ZA (Panel LC470WUF (SD)(P1)), LG 32LW4500 ZB (Panel LC320EUD (SD)(P1)), LG 42LW4500 ZB (Panel LC420EUF (SD)(PX)), LG 42LV4500 DA (Panel LC420EUF (SD)(A1)), LG 32LV4500 (Panel LC320EUD (SD)(A4)), LG 42LV369C (Panel T420HW08 V.9).
PSU Advanced
The EAX63729001 / 7 power supply module is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC assembly is a Step-Up Converter based on the FAN7930B PWM controller, which evenly distributes high-frequency impulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 42LV3500:
Installed matrix (LED-panel) LC420EUN (SD) (V3) or T420HW08 V.1.
The matrix control uses the Timing Controller (T-CON) 6870C-0368A.
The LED driver 3PEGC20008B-R is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 42LV3500 TV are generated by the EAX63729001 power supply module or its analogs using FAN7930B (PFC), 3BR4765JZ (Standby DIP-7), L6599AD (PWM Resonant) microcircuits, and K10A60D type power switches.
MainBoard - the main board (motherboard) is an EAX64290501 module, using CPU chips: LGE107DC-RP, DDR: H5TQ1G63DFR-PBC, NAND: 01GW3B2CN6E, SPI FLASH: 25Q80BVSIG and others.
The TDTJ-S001D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUN-SDV3
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 360 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V