Technical description and composition of the LG 42LA660S TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LA660S ZA 42LA660V
Chassis / Version: LD33B / LC33B / LE33B
Panel: LC420EUH (PF) (P1) 120 Hz
LED backlight: 6920-0001C 2 * 57 led; cool: 6922L-0072A
LED driver (backlight): integrated into PSU; 67.2V, 0.9A
PWM LED driver: R5F100BCAFP, IW7011
MOSFET LED driver: TK15A20D
Power Supply (PSU): EAX64905701 (2.6) - EAY62810901, PLDF-L211A, LGP4247-13LPB
PWM Power: SSC9527S (PWM Resonant), R2A20133D (PFC), ICE3BR4765JZ (Standby)
MOSFET Power: 13NM60N, 10NM60N
MainBoard: EAX64797004 (1.1)
IC MainBoard: CPU: MTK 5398
Tuner: TDSQ-G501 (B) EBL6120403
Control: WIFI: TWFM-B006D
Specifications 42LA660S
LG 42LA660S
General repair guidelines for TV LCD LED
Repair of electronic equipment usually begins with its external inspection and diagnosis of the malfunction. In this case, you should inspect all the internal components of the LG 42LA660S ZA TV, as well as the external elements of the housing. According to some external signs of a change in the state of some elements, it is sometimes possible to make assumptions about the nature of the defect, as well as determine the further direction of the troubleshooting. If ring cracks are detected in the soldering of the terminals of the elements or dangling connecting tracks, swollen capacitors or charred resistors - all this can be characteristic signs of the causes or consequences of an already known typical malfunction.
Sometimes the LG 42LA660S TV just does not turn on. No control lights on the front panel are lit or blinking, the TV does not respond to the remote control and does not make any sounds or any signs of life when turned on. The most likely cause of the malfunction is the failure of the EAY62810901 common power supply module. If it is working properly, you need to check the processor batteries on the SSB (Main Board). 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 the LG 42LA660S does not have an image, but there is sound, a malfunction of the backlight LEDs of the LC420EUH-PFP1 panel (120Hz) or their power converter may be malfunctioning. You should also make sure that the electrolytic capacitors of the secondary rectifiers of the common power supply are working.
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 lines and connectors.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required.
The EAX64797004 (1.1) motherboard must be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or lights up continuously. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary.
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 - CPU: MTK 5398 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.
Before changing the TDSQ-G501 (B) EBL6120403 tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding tuner pins.
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.
LED backlight 6922L-0072A (cool);
Led 42 V13 APT TV REV 0.4 1 L-Type 6920L-0001C;
42 V13 APT TV REV 0.4 1 R-Type 6920L-0001C
Schematic diagram ------------> LG CHASSIS: LA01U; MODEL: 42LA660, 42LA660S, 42LA660V, 42LA662V, 42LA667V 42LA669V (CHASSIS LD33B) SERVICE MANUAL.
Schematic diagram PSU ---------> LGP4247-13LPB
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)).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the EAX64905701 module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the R2A20133D PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 42LA660S:
Installed matrix (LED-panel) LC420EUH (PF) (P1) 120 Hz.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller R5F100BCAFP, IW7011. As the power elements of the LED driver, keys of the TK15A20D type are used.
The necessary supply voltages for all nodes of the LG 42LA660S TV are generated by the EAX64905701 power supply module or its analogs using SSC9527S (PWM Resonant), R2A20133D (PFC), ICE3BR4765JZ (Standby) microcircuits and power switches of the 13NM60N, 10NM60N type.
MainBoard - the main board (motherboard) is an EAX64797004 module, using CPU chips: MTK 5398 and others.
Tuner TDSQ-G501 (B) EBL6120403 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUH-PFP1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 400 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + Dithering), CIE1931 68%
Response Time: 8/10 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: EPI, 100 pins
Voltage: 12.0V