Friday 14 February 2020

REPAIR / SERVICING TV LG 32LA620V

Technical description and composition of the LG 32LA620V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 32LA620V
Chassis / Version: LD33B
Panel: LC320DUE (SF) (U1)
LED backlight: 6916l-1439A & 6916l-1440A
T-CON: LC500DUE-SFR1 6870C-0452A
LED driver (backlight): integrated into PSU; 51.8V 400mA
PWM LED driver: BD9483 (BD9483F)
MOSFET LED driver: FDT86106, AP18N20GH, STF19NF20
Power Supply (PSU): LGP32-13PL2 EAX64881301 (1.7) EAY62830901
PWM Power: 3BR4765JZ (Standby), SC1S311 (PWM flyback), NR891D (PWM Step-down)
MOSFET Power: 19NF20, MDF11N65B, MBRF10U200CT
MainBoard: EAX64797004 (1.1)
IC MainBoard: LGE2122 1402-BTAN, NAND: 3DAI8 JW857, H5TQ4G63AFR
Tuner: EBL61240503 TDSQ-G601D (B)
Control: WIFI MODULE TWFM-B006D
Specifications 32LA620V
LG 32LA620V
General repair guidelines for TV LCD LED
Any repair usually begins with an external inspection. 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 often guess 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.
In the case when the 32LA620V does not turn on, does not respond to the remote control and the front panel buttons, does not blink bulbs and does not show any signs of operability, the EAX64881301 power supply module (1.7) is probably faulty in this case. It is advisable to start the troubleshooting of the power supply module by checking the state of the electrolytic capacitors of the rectifier filters and the mains fuse. Defective capacitors should be replaced. If the mains fuse is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and transistors, which are often found in such a state of 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.
If the LG 32LA620V TV does not have an image, but there is sound, a malfunction in the backlight circuits of the LC320DUE LED panel is likely.
Often in the absence of backlighting, disassembling the panel is required. It is necessary to check the serviceability of the transitions of the LEDs, as well as the reliability of the contact connections in the rulers and connectors.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can test each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the LED will light up slightly.
If the motherboard NC4_M_TU24 LD33B / LC33B / LE33B EAX64797004 (1.1) 07/13/10 B.K.H is faulty, first of all it is necessary to check all the linear stabilizers and power converters of its chips, and also, if necessary, update the software (software). Sometimes you can check the health of MB only by replacement.
Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - LGE2122 1402-BTAN, NAND: 3DAI8 JW857, H5TQ4G63AFR and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
The malfunction of the tuner EBL61240503 TDSQ-G601D (B) is established after checking the software and all supply voltages at its terminals.
For owners of 32LA620V TVs, we recommend that you contact qualified professionals with experience to repair! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!
One of the typical malfunctions of the LG 32LA620V often occurs in the LG panel LC320DUE (SF) (U1).
External manifestations: there is no image, the backlight does not work. In most such cases, the LEDs turn out to be malfunctioning, which during testing turn out to be either in a cliff or with broken internal zener diodes.
LEDs must be replaced, and the maximum current from the driver should be limited to 10-20%.

More details on this page

PSU SCHEMATIC ---------------> LG LGP32-13PL2, LGP32I-13PL2 LGP32-13PL2 EAX64881301 EAY62830901



 The appearance of the MainBoard EAX64797004 is shown in the figure below:
EAX64797004
EAX64797004 can be used in TVs:
LG 42LA660S ZA 42LA660V (Panel LC420EUH (PF)(P1) 120 Hz), LG 32LA620V (Panel LC320DUE (SF)(U1)), LG 42LN570V (Panel LC420DUE (SF)(R3)), LG 50LA620V ZA (Panel LC500DUE (SF)(U1)), LG 32LN575S (Panel LC320DUE (SF)(R1)), LG 42LA669V 42LA669V-ZE.BRUZLJU (Panel LC420EUH (PF)(P1)).
The appearance of the power supply
Main features of the device LG 32LA620V:
Installed matrix (LED-panel) LC320DUE (SF) (U1).
The matrix control uses the Timing Controller (T-CON) LC500DUE-SFR1.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the BD9483 PWM controller (BD9483F). As the power elements of the LED driver, keys of the type FDT86106, AP18N20GH, STF19NF20 are used.
The necessary supply voltages for all nodes of the LG 32LA620V TV are generated by the LGP32-13PL2 power supply module or its analogs using 3BR4765JZ (Standby), SC1S311 (PWM flyback), NR891D (PWM Step-down) microcircuits and power switches of the type 19NF20, MDF11N65B, MBRF1010 .
MainBoard - the main board (motherboard) is an EAX64797004 module, using LGE2122 1402-BTAN chips, NAND: 3DAI8 JW857, H5TQ4G63AFR and others.
The tuner EBL61240503 TDSQ-G601D (B) provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC320DUE-SFU1
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 698.4x392.85 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 300 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V