Thursday 20 February 2020

REPAIR / SERVICING TV LG 32LV571S

Technical description and composition of the LG 32LV571S TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 32LV571S
Chassis / Version: LD12D / E
Panel: LC320EUD (SD) (F3)
T-CON: 6870C-0358A VER1.0 V6 32.42.47
LED driver (backlight): 6917L-0047A 3PDGC20001B-R - PCLC-D002 B REV0.4
Power Supply (PSU): EAX62865601 / 8 REV1.1 LGP3237-11SP
PWM Power: FAN7930B (PFC), ICE3BR4765JZ (Standby), L6599AD (PWM Resonant L6599AI)
MOSFET Power: K10A60D
MainBoard: EAX64104702 / EAX64405401 / EBR73503601
IC MainBoard: LGE35230, K4B2G1646C-HCKO, TH58DVG4S0ETA20, NTP7400L, F0514A, M24C16
Tuner: TDFR-G256D
Specifications 32LV571S
LG 32LV571S
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 32LV571S TV does not turn on, does not respond to the remote control and the control panel buttons, and does not blink with any indicators.
Often in such cases, the EAX62865601 power module is faulty. Then, first of all, you should check the performance of ICE3BR4765JZ (PWM Standby). It is also necessary to measure the output voltages of other converters (main source and PFC) and, if they are absent, it is necessary to check the operability of power switches (K10A60D) and rectifier diodes for possible short circuit.
In case of breakdowns in the secondary circuits, the converter can emergencyly operate in the short circuit mode, and during short circuit in the primary circuit the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback.
PWM chips FAN7930B (PFC), ICE3BR4765JZ (Standby), L6599AD (PWM Resonant L6599AI) are checked by replacing with obviously good ones.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
In most cases, the malfunction is caused by the lack of a backlight display. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX64104702 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Board repair and replacement of LGE35230, K4B2G1646C-HCKO, TH58DVG4S0ETA20, NTP7400L, F0514A, M24C16 microcircuits are carried out with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be 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 TDFR-G256D 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.
It should be remembered! Attempts to self-repair the LG 32LV571S TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!


SCHEMATIC MANUAL -----------------------> LG CHASSIS : LD12E; MODEL: 32LV570G/570S/571S, 32LV570G/570S-ZB 32LV571S-ZA SERVICE MANUAL.


SCHEMATIC MANUAL -----------------------> EAX62865601 rev1 LGP3237-11SPC1 Power Supply schematic


 The appearance of the MainBoard EAX64104702 is shown in the figure below:
EAX64104702
The appearance of the power supply
Main features of the device LG 32LV571S:
Installed matrix (LED-panel) LC320EUD (SD) (F3).
The matrix control uses the Timing Controller (T-CON) 6870C-0358A.
The LED driver 6917L-0047A is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 32LV571S TV are generated by the EAX62865601 power supply module or its analogs using FAN7930B (PFC), ICE3BR4765JZ (Standby), L6599AD (PWM Resonant L6599AI) microcircuits and K10A60D type power switches.
MainBoard - the main board (motherboard) is an EAX64104702 module using LGE35230, K4B2G1646C-HCKO, TH58DVG4S0ETA20, NTP7400L, F0514A, M24C16 and other chips.
The TDFR-G256D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC320EUD-SDF3
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 10%), Hard coating (2H)
Brightness: 400 cd / m²
Contrast Ratio: 1600: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + Dithering)
Response Time: 5 (G to G); 6 (MPRT)
Frequency: 120Hz + 120Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (4 ch, 8/10-bit), 92 pins
Voltage: 12.0V