Friday 14 February 2020

REPAIR / SERVICING TV LG 32LA621V

Technical description and composition of the LG 32LA621V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 32LA621V ZD
Chassis / Version: LD33B
Panel: LC320DUE (SF) (U1)
LED backlight: 6916l-1439A & 6916l-1440A
T-CON: LC500DUE-SFR1 - 6870C-0452A; TL2354EP, TPS65178A, TPS6598
LED driver (backlight): integrated into PSU; 51.8V 400mA
PWM LED driver: BD9483F
MOSFET LED driver: STF19NF20, FDT86106, AP18N20GH
Power Supply (PSU): EAX64881301 (1.6) LGP32-13PL2 EAY62830901
PWM Power: 3BR4765JZ (ICE 3BR4765JZ Standby DIP-8), SC1S311 (S SC1S311A PWM flyback), NR891D (PWM Step-down)
MOSFET Power: 19NF20, MDF11N65B, MBRF10U200CT
MainBoard: EAX64797003 (1.2)
IC MainBoard: NAND flash: H5TQ4G63AFR (SAA36403530 VER.03.11.03), H5TQ2G63AFR, NTP7513
Tuner: EBL61240503 TSQ-G601D (B)
Control: WIFI: TWFM-B006D, IR: MC28A 1BF-3032A LA6200
Specifications 32LA621V
LG 32LA621V
General repair guidelines for TV LCD LED
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. 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 19NF20, 20NF20, MDF11N65B, MBRF10U200CT, which are often found in such a breakdown state.
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 32LA621V TV does not have an image, but there is sound, a malfunction in the backlight circuits of the LED panel LC320DUE (SF) (U1) is likely.
The lack of backlight often occurs due to an open circuit in the LED circuit. There is a need for disassembling the panel and checking the LEDs themselves, as well as the same contact 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 is required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
If the motherboard EAX64797003 (1.2) 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.
In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - NAND flash: H5TQ4G63AFR (SAA36403530 VER.03.11.03), H5TQ2G63AFR, NTP7513 which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Before replacing the tuner EBL61240503 TSQ-G601D (B), if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus

For owners of 32LA621V 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 32LA621V ZD 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


SCHEMATIC MANUAL ------>LG CHASSIS: LD33B, MODEL: 32LA62** 32LA62**-Z*.


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


The appearance of the MainBoard EAX64797003 is shown in the figure below:
EAX64797003
EAX64797003 can be used in TVs:
LG 42LA620V (Panel LC420DUE (SF)(U1)), LG 32LN570V (Panel LC320DUE (SF)(R1)), LG 50LA644V (Panel LC500EUN (SF)(F1)), LG 47LA660V (Panel LC470EUG (PF)(F1)), LG 47LA621V (Panel LC470DUE (SF)(U1)), LG 42LA644V (Panel LC420EUN (SF)(F2)), LG 39LA620V ZA (Panel T390HVJ01.0), LG 42LA621V ZD (Panel LC420DUE (SF)(U1)), LG 32LA621V ZD (Panel LC320DUE (SF)(U1)), LG 32LN655V (Panel LC320EUB (PF)(M1)), LG 42LA667V (Panel LC420EUH (PF)(P1) ), LG 47LN613V (Panel LC470DUE (SF)(R4)), LG 32LA667V ZB (Panel LC320EUB (PF)(P1)), LG 55LA660V ZA (Panel LC550EUH (PF)(P1)), LG 47LA620V ZA (Panel LC470DUE (SF)(U1)), LG 32LN613V ZB (Panel LC320DUE (SF)(R4)), LG 42LN655V ZB.BRUZLJU (Panel LC420EUH (PF)(M1)), LG 32LA644V ZA (Panel LC320EUN (SF)(F1)), LG 42LN613V (Panel LC420DUE (SF)(R4)), LG 47LA690V ZB (Panel LC47EUH (PF)(P1)), LG 47LA662V (Panel LC470EUG (PF)(F1)), LG 42LA645V 42LA645V-ZC.BRUYLJU (Panel LC420EUN (SF)(F3)), LG 32LA660V (Panel LC320EUB (PF)(P1)), LG 47LA644V 47LA644V-ZA (Panel LC470EUN (SF)(F2)), LG 50LA667S (Panel T500HVD02.1), LG 47LA691V (Panel LC470EUH (PF)(P1)), LG 32LA662V (Panel LC320EUB (PF)(P1)).
The appearance of the power supply
Main features of the device LG 32LA621V:
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, controlled by the BD9483F PWM controller. As the power elements of the LED driver, keys such as STF19NF20, FDT86106, AP18N20GH are used.
The necessary supply voltages for all nodes of the LG 32LA621V TV are generated by the EAX64881301 power supply module or its analogs using 3BR4765JZ (ICE3BR4765JZ Standby DIP-8), SC1S311 (SSC1S311A PWM flyback), NR891D (PWM Step-downNF), and power modules MDF11N65B, MBRF10U200CT.
MainBoard - the main board (motherboard) is an EAX64797003 module using NAND flash chips: H5TQ4G63AFR (SAA36403530 VER.03.11.03), H5TQ2G63AFR, NTP7513 and others.
The tuner EBL61240503 TSQ-G601D (B) provides the reception of television programs and tuned 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