Thursday, 27 February 2020

REPAIR / SERVICING TV LG 42LG6000-ZA

Technical description and composition of the LG 42LG6000-ZA TV, panel type and applicable modules. The composition of the modules.
LG
Model: 42LG6000-ZA
Chassis / Version: LD89F
Panel: LC420WUF (SA) (A1)
T-CON: EAX41602202
Inverter (backlight): integrated into PSU; 950V 135mA
PWM Inverter: OZ9966SN
MOSFET Inverter: 5N50CF
Power Supply (PSU): PLHL-T715A - EAY41971801 REV 8.6 - 2300KEG027A-F
PWM Power: UCC28060 (PFC 16pin), LAF0001 (FAN7601)
MOSFET Power: K4013, K4012
MainBoard: EAX39192001 (14)
IC MainBoard: CPU: FLI10620H-AA, FLASH: HY27US08121B-TPCB, EEPROM: AT24C16AN, EEPROM: 24LC512; FLi10620H, NTP-3000A
Tuner: TDFV-G135D1
Specifications 52LG5030
LG 42LG6000-ZA
General recommendations for repairing TV LCD
Repair LG TV with chassis LD89F. it is advisable to start with a careful external examination of both internal and external elements. Sometimes, based on visible changes in the components of the device, it is possible to draw some conclusions and determine the direction of further troubleshooting, even before the necessary measurements are taken. 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.
In cases when the LG 42LG6000-ZA TV does not turn on, does not respond to the remote control and buttons, no indicators on the front panel light up or blink, and there are no sounds and no signs of operability when turning on, the power module is most likely faulty or there is no power processor on the motherboard (a typical defect of some LG TVs). In the absence of swollen filter capacitors of the secondary rectifiers, the diagnostics of the power supply should be started by checking the fuse and, if it is broken, it is first necessary to check all the power semiconductor elements of the primary circuit - diodes and transistors for the possibility of an avalanche or thermal breakdown.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
If the LG 42LG6000-ZA TV does not have an image, but there is sound, the malfunction should be sought in the backlight lamp power converter (inverter). It is also necessary to check the serviceability of the electrolytic capacitors of the filter of the secondary rectifiers of the PSU (power supply) for an overstated ESR. When diagnosing a malfunction of the inverter with the protection off, special precautions must be taken, because there is a risk of failure of the power elements of the inverter. After diagnosis, it is imperative to restore the protection circuits for the inverter to operate normally.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair only to professionals with sufficient experience in the field of electronic equipment repair.


SCHEMATIC DIAGRAM --------->  LG 42LG6000, 42LG6000-ZA, 42LG6100, 42LG6100-ZB Chassis LD89F


 The appearance of the MainBoard EAX39192001 is shown in the figure below:
EAX39192001
EAX39192001 can be used in TVs:
LG 42LG6000-ZA (Panel LC420WUF (SA) (A1)), LG 32LG6000 (Panel LC320WXN (SA) (A1)).
PSU Advanced
The PLHL-T715A 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 node is a Step-Up Converter based on the UCC28060 16pin 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 42LG6000-ZA:
Installed matrix (LCD panel) LC420WUF (SA) (A1).
The matrix control uses the Timing Controller (T-CON) EAX41602202.
To power the backlight, a converter is used, combined with a power supply, controlled by the OZ9966SN PWM controller. As power elements of the inverter, keys of the 5N50CF type are used.
The necessary supply voltages for all nodes of the LG 42LG6000-ZA TV are generated by the PLHL-T715A power supply module or its analogs using UCC28060 (PFC 16pin), LAF0001 (FAN7601) microcircuits and power switches of the K4013, K4012 type.
MainBoard - the main board (motherboard) is an EAX39192001 module using CPU chips: FLI10620H-AA, FLASH: HY27US08121B-TPCB, EEPROM: AT24C16AN, EEPROM: 24LC512; FLi10620H, NTP-3000A and others.
The TDFV-G135D1 tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC420WUF-SAA1
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 13%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1300: 1
Display Colors: 1.06B (8-bit + Dithering)
Response Time: 8 (MPRT)
Frequency: 120Hz
Lamp Type: 18 pcs EEFL Without Driver
Signal Interface: LVDS (4 ch, 10-bit), 92 pins
Voltage: 12.0V