Monday, 2 March 2020

REPAIR / SERVICING TV LG 47LA643V

Technical description and composition of the LG 47LA643V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 47LA643V ZB
Chassis / Version: LD31B
Panel: LC470EUN (SF) (F2)
LED backlight: 6920L-0001C, 47 V13 Edge REV0.4 1 L-TYPE / R-TYPE
T-CON: 6870C-0444A LC470DUE-SFR1_Control_Ver 1.0
LED driver (backlight): 6917L-0117A - 3PHCC20005A-H PLCH-D201 A REV0.7
Power Supply (PSU): EAX64908101 (2.2) REV1.0 - LGP4755-13P EAY62851201
PWM Power: L6599AD (PWM Resonant), R2A20133DSP (PFC), FSD106LG (Standby)
MOSFET Power: STD13NM60N
MainBoard: EAX64891306 (1.1) - EBR76922716
IC MainBoard: CPU: LGE2121-MC, DRAM: H5TQ2G63DFR, Flash: MX25L8006E, AUDIO: STA380BWF
Tuner: TDSQ-G601D (B) EBL61240503
Control: IR: EBR76405702 LA6400
Specifications 47LA643V
LG 47LA643V
General repair guidelines for TV LCD LED
Malfunctions of the EAX64908101 (2.2) REV1.0 - LGP4755-13P power supply module can be expressed in different ways, for example, LG 47LA643V does not turn on at all and the control lights on its front panel do not light up and do not blink, there are no signs of operability. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is broken in the power supply, in most cases a breakdown of the power key (s) STD13NM60N is detected, which can be integrated with a PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
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 there is no image when you turn on the LG 47LA643V, or it appears and immediately disappears, but there is sound, most likely there is a malfunction in the backlight LED circuit of the LC470EUN (SF) (F2) panel, or in the LED node of the driver-converter of their power supply.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for an open circuit, as well as the reliability of the connections in the connectors and rations of the terminals.
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.
When trying to repair the motherboard, you should first check the serviceability of linear stabilizers or power converters of microcircuits and, if necessary, update the software (software).
If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - CPU: LGE2121-MC, DRAM: H5TQ2G63DFR, Flash: MX25L8006E, AUDIO: STA380BWF. Defective components should be replaced.
If a tuner TDSQ-G601D (B) EBL61240503 is suspected of malfunction, it is first necessary to verify the correctness of the software, as well as the presence of the necessary power supply voltage levels and data exchange pulses with the processor via the I2C bus on the corresponding tuner pins.
Once again, remind users! Attempts to self-repair the LG 47LA643V TV without the appropriate qualifications and experience can lead to its complete non-repairability!


Service manual and schematic diagram -------------->  LG CHASSIS: LD31B; MODEL: 47LA643V, 47LA643V-ZB..

  schematic diagram -------------->  LGP4755-13P EAX64908101 Power Supply schematic diagram


 The appearance of the MainBoard EAX64891306 is shown in the figure below:
EAX64891306
EAX64891306 can be used in TVs:
LG 32LN540V (Panel LC320DUE (SF)(R1)), LG 42LN542V-ZD (Panel LC420DUE SFR3), LG 32LN541V (Panel LC320DUE (SF)(R1)), LG 42LA615V (Panel LC420DUE (SF)(U2) ), LG 32LA615V (Panel LC320DUE (SF)(U2)), LG 42LN540V (Panel LC420DUE (SF)(R1)), LG 42LN541V (Panel LC420DUE (SF)(R1)), LG 47LN540V (Panel LC470DUE (SF)(R1)), LG 32LB530U ZA (Panel LC320DXE (SG)(R1)), LG 39LN540V (Panel HC390DUN-VCFP1-11XX), LG 32LA643V (Panel LC320EUN (SF)(F1)), LG 32LN542V (Panel LC320DUE SF R1), LG 47LA615V (Panel LC470DUE (SF)(U2)), LG 47LA643V ZB (Panel LC470EUN (SF)(F2)), LG 32LN541U ZB (Panel HC320DXN-VHFP1 - 21XX / HC320DXN-VHFPA - 21XX), LG 32LN536U (Panel NC320DXN (SA)(P1)), LG 37LN541U (Panel LC370DXE (SF)(R1)).
PSU Advanced
The EAX64908101 power supply module is made using a Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC node is a Step-Up Converter based on the R2A20133DSP PWM controller, which evenly distributes high-frequency pulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 47LA643V:
Installed matrix (LED-panel) LC470EUN (SF) (F2).
The matrix control uses the Timing Controller (T-CON) 6870C-0444A.
The LED driver 6917L-0117A is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 47LA643V TV are generated by the EAX64908101 power module or its analogs using L6599AD (PWM Resonant), R2A20133DSP (PFC), FSD106LG (Standby) microcircuits and power switches of the STD13NM60N type.
MainBoard - the main board (motherboard) is an EAX64891306 module using CPU chips: LGE2121-MC, DRAM: H5TQ2G63DFR, Flash: MX25L8006E, AUDIO: STA380BWF and others.
Tuner TDSQ-G601D (B) EBL61240503 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC470EUN-SFF2
Type: a-Si TFT-LCD, Panel
Diagonal size: 47 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 1039.68x584.82 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 350 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V