Technical description and composition of the LG 47LA621V TV, type of panel and applicable modules. The composition of the modules.LG LED
Model: 47LA621V
Chassis / Version: LD33B
Panel: LC470DUE (SF) (U1)
T-CON: 6870C-0444A, LC470DUE-SFR1
LED driver (backlight): integrated into PSU; 93.2 ~ 118.5V 0.4A
PWM LED driver: BD9483F
MOSFET LED driver: MDD7N25, FDT86106
Power Supply (PSU): EAX64905501 (2.2), LGP4750-13PL2 EAY62810801
PWM Power: SSC9527S (PWM Resonant), R2A20133D (PFC), ICE3BR4765JZ (Standby)
MOSFET Power: 13NM60N
MainBoard: EAX64797003 (1.2) - EBR76823128, SAA36403538, SAA36403509
IC MainBoard: CPU: LGE2122, NAND: SAA36403538 VER. 3.20.33, H5TQ4G63AFR, SOUND: NTP7513
Tuner: EBL61240503 TDSQ-G601D (B)
Control: AKB73756502; IR EBR77031901, RSD7CG000P, MC28A, 1BF-3032A, LA6200 IR Ver1.2
Specifications 47LA621V
LG 47LA621V
General repair guidelines for TV LCD LED
If the LG 47LA621V does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a malfunction of the EAX64905501 (2.2) power module, LGP4750-13PL2. In some cases, only the processor power regulator may be faulty. 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.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is verified by replacing it with a known good one.
If there is no image when you turn on the LG 47LA621V, or it appears and immediately disappears, but there is sound, most likely there is a malfunction in the backlight LED circuit of the LC470DUE (SF) (U1) panel, or in the LED node of the driver-converter of their power supply.
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.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
Repair of the motherboard EAX64797003 (1.2) - EBR76823128, SAA36403538, SAA36403509 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.
If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - CPU: LGE2122, NAND: SAA36403538 VER. 3.20.33, H5TQ4G63AFR, SOUND: NTP7513. Defective components should be replaced.
If the TV works normally from external devices, but does not tune to television channels, the tuner EBL61240503 TDSQ-G601D (B) 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.
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.
Service manual and schematic diagram --------------> LG CHASSIS LD33B, MODEL 47LA62** 47LA62**-Z*.
schematic diagram --------------> LGP4750-13PL2 EAX64905501 EAY62810801 power supply.
Wi-fi module: EAT61813901 TWFM-B006D BEJTWFMB006D.
You can reduce the backlight current in TVs with LGP4750-13PL2 power supplies (EAX64905501) as follows. Current sensors in the R811-R818 LEDs - channel 1 and R829-R836 - channel 2. Resistors in the channels in pairs of 4.3 + 3.9 Ohm. You can reduce the backlight current by 25% by removing one pair of resistors in each channel.
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)).
PSU Advanced
The 47LA621V model uses the EAX64905501 power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, this is a boost converter based on the R2A20133D PWM controller, which eliminates the charge current of the rectifier filter's electrolytic capacitor directly from the network through open diodes when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
The appearance of the power supply
Main features of the device LG 47LA621V:
Installed matrix (LED-panel) LC470DUE (SF) (U1).
The matrix control uses the Timing Controller (T-CON) 6870C-0444A.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the BD9483F PWM controller. As power elements of the LED driver, keys of the type MDD7N25, FDT86106 are used.
The necessary supply voltages for all nodes of the LG 47LA621V TV are generated by the EAX64905501 power module or its analogs using SSC9527S (PWM Resonant), R2A20133D (PFC), ICE3BR4765JZ (Standby) microcircuits and 13NM60N power switches.
MainBoard - the main board (motherboard) is an EAX64797003 module using CPU chips: LGE2122, NAND: SAA36403538 VER. 3.20.33, H5TQ4G63AFR, SOUND: NTP7513 and others.
The tuner EBL61240503 TDSQ-G601D (B) provides the reception of television programs and tuning to channels.