Technical description and composition of the LG 32LD420 TV, panel type and applicable modules. The composition of the modules.LG
Model: 32LD420 ZA
Chassis / Version: LD01B
Panel: LC320WUG (SC) (A1)
T-CON: 6870S-0964C & 6870S-0965C (not removable)
Inverter (backlight): integrated into PSU
PWM Inverter: BD9270F
Power Supply (PSU): EAX61124202 / 2
PWM Power: STR-W6053N, HS01G (PFC)
MOSFET Power: 10NM60N
MainBoard: EAX61354204 (0)
IC MainBoard: CPU: LGE107DC-RP, DDR: H5TQ1G63BFR-H9C, Nand: HY27UF082G2B, SPI FLASH MX25L8005M2I
Tuner: TDTJ-S001D
Control: IR: 0XDA35V2.0E
Specifications 32LD420
LG 32LD420
General recommendations for repairing TV LCD
Repair of electronic devices, including the LG 32LD420 ZA TV, it is advisable to start with an external examination of its external and internal elements. Often, based on certain external signs, it may be possible to draw certain conclusions about the reasons for the failure of certain elements of the circuit even before the necessary measurements are made, which will determine the further algorithm for troubleshooting and localizing the defect. In most cases, the repairman can guess the causes of the defect and possible consequences from the characteristic signs of typical TV defects, for example, ring cracks formed in the soldering of the element leads, swollen rectifier filter capacitors, charred resistors and other circuit elements.
Sometimes the LG 32LD420 TV just doesn’t turn on. No control lights on the front panel are lit or blinking, the TV does not respond to the remote control and does not make any sounds or any signs of life when turned on. The most likely cause of the malfunction is the failure of the EAX61124202 / 2 common power supply module. If it is working properly, you must check the standby batteries on the Main Board. Diagnostics and repair of the common power supply should always begin with a check of the mains fuse and the condition of the electrolytic capacitors of the secondary rectifier filters. Defective and swollen capacitors should be replaced with new ones. If the fuse breaks, it is advisable to check for a breakdown, first of all, all the power semiconductor elements of the converter and the diode bridge of the rectifier network, as well as the large electrolytic capacitor of the filter of the rectifier network.
Mos-Fet keys used in switching power supplies (SMPS) rarely fail for no reason to look for when checking other circuit elements. Often the breakdown is caused by malfunctions of electrolytic capacitors or semiconductor elements in the primary circuit, or by a break in the resistors in the stabilization circuits. The PWM controller chip STR-W6053N, HS01G (PFC) can also cause a breakdown of the power switch of the converter.
If the LG 32LD420 does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter 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 inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors. When disabling protection in order to enable the diagnosis of a malfunction, special care should be taken, and after completion of all repair work, it is necessary to restore the circuit and the inverter protection for further safe operation of the TV.
In cases of attempts to repair the motherboard EAX61354204 (0), it is necessary to check the operability of the linear stabilizers and power converters of its microcircuits and, if possible, update the software (software). BGA chips can sometimes be diagnosed with local heating. Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the CPU elements: LGE107DC-RP, DDR: H5TQ1G63BFR-H9C, Nand: HY27UF082G2B, SPI FLASH MX25L8005M2I. BGA chip malfunctions are usually easy to detect by warming up.
If the TV works normally from external devices, but does not tune into television channels, the TDTJ-S001D tuner may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
It is necessary to remember to users that attempts to self-repair the LG 32LD420 TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
Service manual and schematic diagram -----------------------------> LG 32LD420 Chassis LD01B
The appearance of the MainBoard EAX61354204 is shown in the figure below:EAX61354204
EAX61354204 can be used in TVs:
LG 32LD345 (Panel LC320WXE-SCA1), LG 37LD450 (Panel LC370WUG (SC)(A1)), LG 42LD455-ZA (Panel LC420WUG), LG 32LD550 (Panel LK315D3LA57), LG 42LD450 ZA (Panel LC420WUG (SC)(A1)), LG LG32LD350 32LD350 (Panel T315HW04 V.8), LG 42LD420 ZA (Panel LC420WUG (SC)(A1)), LG 37LD420 ZA (Panel T370HW03 V.B), LG 32LD420 ZA (Panel LC320WUG (SC)(A1)), LG 32LD555 ZC (Panel LC320WUG (SC)(A1)), LG 26LD355-ZA (Panel T260XW04 V.3), LG 37LD425 ZA (Panel T370HW03 V.B), LG 32LD425 (Panel LC320WUG (SC)(A1)), LG 32LD340 32LD340-ZA.BRUWLJU (Panel LC320WXE (SC)(A1)).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the EAX61124202 / 2 module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the HS01G PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 32LD420:
Installed matrix (LCD panel) LC320WUG (SC) (A1).
The matrix control uses the Timing Controller (T-CON) 6870S-0964C.
To power the backlight, a converter is used, combined with the power supply, controlled by the BD9270F PWM controller.
The necessary supply voltages for all nodes of the LG 32LD420 TV are generated by the EAX61124202 power supply module or its analogs using STR-W6053N, HS01G (PFC) microcircuits and 10NM60N power switches.
MainBoard - the main board (motherboard) is an EAX61354204 module using CPU chips: LGE107DC-RP, DDR: H5TQ1G63BFR-H9C, Nand: HY27UF082G2B, SPI FLASH MX25L8005M2I and others.
The TDTJ-S001D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC320WUG-SCA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 698.4x392.85 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1500: 1
Display Colors: 1.06B (8-bit + FRC), CIE1931 72%
Response Time: 8/10 (Tr / Td)
Frequency: 60Hz
Lamp Type: 14 pcs EEFL Without Driver
Signal Interface: Mini LVDS, 120 pins
Voltage: 3.3 / 16V (VCC / VDD)