Technical description and composition of the LG 37LD425 TV, panel type and applicable modules. The composition of the modules.LG
Model: 37LD425 ZA
Chassis / Version: LD01B
Panel: T370HW03 V.B
T-CON: T370HW03 VB
Inverter (backlight): integrated into PSU
PWM Inverter: BD9270F
Power Supply (PSU): EAX61124202 / 2 LGP37-10LA1
PWM Power: STR-W6053N, HS01G (PFC)
MOSFET Power: 10NM60N
MainBoard: EAX61354204 (0) // EAX63329201 (9)
IC MainBoard: CPU: LGE107DC-RP, DDR: H5TQ1G63BFR-H9C, Nand: HY27UF082G2B, SPI FLASH MX25L8005M2I
Tuner: TDTJ-S001D
Control: AKB72915207, IR: 37-42-47 LD420
Specifications 37LD425
LG 37LD425
General recommendations for repairing TV LCD
Diagnostics of malfunctions and repairs LG 37LD425 ZA, as well as other electronic devices, it is recommended to start with an external examination of the external and internal 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. Experienced repairmen are often aware of the causes of the defect and possible consequences, for example, from ring cracks in the soldering of the leads of the elements, as well as from swollen capacitors or resistors burnt to coal dust and other external signs of certain malfunctions.
If the TV does not turn on, no indicators on its front panel are lit or blinking. Also, if the TV does not respond to the remote control and buttons, it does not make any sounds or any signs of operability when it is turned on, there is a certain chance that the EAX61124202 / 2 LGP37-10LA1 power supply module is defective and needs repair. Sometimes with similar manifestations a problem can only occur in the absence of standby power. When diagnosing and repairing the power supply, first of all, replace the swollen capacitors of the filter of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
If a breakdown of the power switch is detected, it should be remembered that in a switching power supply (IIP) it does not fail by itself without any reasons that should be sought by checking other elements of the primary circuit - electrolytic capacitors, PWM controller STR-W6053N, HS01G (PFC), which can only be checked by replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
If the LG 37LD425 does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction of the display backlight, or their power converter - inverter. Sometimes when you turn on the image appears and disappears immediately. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the inverter itself, including in the secondary rectifier of the main PSU. It should be remembered that when protection is disabled in order to diagnose a malfunction, there is always a risk of failure of the power elements of the inverter. After repair, it is necessary to restore all standard converter protection circuits.
Repair of the EAX61354204 (0) 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, to repair the MB board (SSB), it may be necessary to replace the chips - CPU: LGE107DC-RP, DDR: H5TQ1G63BFR-H9C, Nand: HY27UF082G2B, SPI FLASH MX25L8005M2I with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the TDTJ-S001D tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
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 CHASSIS: LD01B; MODEL: 37LD420/420N, 37LD420/420N-ZA, 37LD425/428, 37LD425/428-ZA, 37LD420C, 37LD420C-ZA
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 LGP37-10LA1 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 37LD425:
Installed matrix (LCD-panel) T370HW03 V.B.
The matrix control uses the Timing Controller (T-CON) T370HW03.
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 37LD425 TV are generated by the EAX61124202 power module or its analogs using STR-W6053N, HS01G (PFC) microcircuits and 10NM60N type 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: AUO
Model: T370HW03 VB
Type: a-Si TFT-LCD, Panel
Diagonal size: 37 inch
Resolution: 1920x1080, FHD
Display Mode: AMVA3, Normally Black, Transmissive
Active Area: 819.36x460.89 mm
Surface: Antiglare (Haze 11%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 5000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: 10 pcs CCFL Embedded (Balance board)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
