LG LED
Model: 42LN542V-ZD
Chassis / Version: LD31B / LD36B
Panel: LC420DUE SFR3
LED backlight: 6916L-1214A, 6916L-1215A, 6916L-1216A, 6916L-1217A
T-CON: LC500DUE-SFR1_Control_Merge 6870C-0452A
LED driver (backlight): integrated into PSU; 157V 341mA
PWM LED driver: MAP3202 (MAP3202SIRH)
MOSFET LED driver: FDT86106, STF10NM60N
Power Supply (PSU): EAX64905301 (2.3) LGP42-13PL1
PWM Power: SSC1S311A (PWM flyback), NR891D (PWM Step-down 24/12)
MOSFET Power: MDF11N65B
MainBoard: EAX64891306 (1.1)
IC MainBoard: CPU: LGE2121-MC, DRAM: H5TQ2G63DFR, Flash: MX25L8006E, AUDIO: STA380BWF
Tuner: TDSQ-G601D
Control: AKB73715603, IR: EBR75421804-103 EAX65034404 (1.0)
Specifications 42LN542V
LG 42LN542V-ZD
General repair guidelines for TV LCD LED
Diagnostics of malfunctions and repairs LG 42LN542V-ZD, as well as other electronic devices, it is recommended to start with an external examination of the external and internal elements. Often, based on certain external signs, it may be possible to draw certain conclusions about the reasons for the failure of certain elements of the circuit even before the necessary measurements are made, which will determine the further algorithm for troubleshooting and localizing the defect. Electrolytic capacitors of filters with a swollen casing, as well as ring cracks formed in the soldered leads of heating elements, or a layer of coal on burnt resistors sometimes tell the repairman the causes of the malfunction and possible consequences.
In the case when the 42LN542V-ZD does not turn on, does not respond to the remote control and buttons on the front panel, does not blink lights and does not show any signs of operability, the LG42-13PL1 power supply module is probably defective in this case. If it is serviceable with such manifestations, it is necessary to check the stabilizer (converter) of the processor power supply on the motherboard. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is cut off in the power supply, in most cases a breakdown of the power key (s) is detected, which can be integrated with the 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.
The reasons for the breakdown of the power switch in switching power supplies (IIPS) can be different, for example, a malfunction of semiconductor cells or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of the PWM controller chip or broken resistors in its bundle.
In cases where the LG 42LN542V-ZD TV has lost its image, and the sound is there and all other functions are operational, there is a possibility of a malfunction of the LED driver (converter for powering the backlight LEDs of the LC420DUE SFR3 panel). When you turn on the TV, the image may appear briefly and disappear immediately. It must be borne in mind that with such manifestations the LEDs themselves also fail.
Often there is a need for disassembling the panel to check the health of the LEDs, as well as contact connections in the connectors and soldering.
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 will be required, and ideally, a current source.
If the motherboard NC4.0 LD31B LC36B is faulty, first of all it is necessary to check all the linear stabilizers or power converters of its chips, and also, if necessary, update the software. Sometimes you can check the health of MB only by replacement.
If you suspect that the TDSQ-G601D tuner is malfunctioning, first of all, you need to make sure that the voltage of the varicaps (30-33V) is on the corresponding output of the tuner, as well as other voltage supplying it.
It should be remembered! Attempts to repair the LG 42LN542V-ZD 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!
Led backlight:
42 ROW2.1 Rev 0.6 1 L1-Type 6916L-1214A;
42 ROW2.1 Rev 0.6 1 R1-Type 6916L-1215A;
42 ROW2.1 Rev 0.6 1 L2-Type 6916L-1216A;
42 ROW2.1 Rev 0.6 1 R2-Type 6916L-1217A; 6637L-0025a.
SCHEMATIC DIAGRAM ----------> LG 42LN54** 42LN54**-Z* Chassis LD31B/LD36B.
SCHEMATIC DIAGRAM ----------> LG 37/39/42 Inch LGP3739-13PL1, LGP42-13PL1.
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)).
The appearance of the power supply
Main features of the device LG 42LN542V-ZD:
Installed matrix (LED panel) LC420DUE SFR3.
The matrix control uses the Timing Controller (T-CON) LC500DUE-SFR1_Control_Merge.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the MAP3202 PWM controller (MAP3202SIRH). As the power elements of the LED driver, keys of the type FDT86106, STF10NM60N are used.
The necessary supply voltages for all nodes of the LG 42LN542V-ZD TV are generated by the EAX64905301 power module or its analogs using SSC1S311A (PWM flyback), NR891D (PWM Step-down 24/12) microcircuits and MDF11N65B type power switches.
MainBoard - the main board (motherboard) is an EAX64891306 module using CPU chips: LGE2121-MC, DRAM: H5TQ2G63DFR, Flash: MX25L8006E, AUDIO: STA380BWF and others.
The TDSQ-G601D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420DUE-SFR3
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 370 cd / m²
Contrast Ratio: 1050: 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