Technical description and composition of the LG 42LS3400 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LS3400
Chassis / Version: LT21C
Panel: LC420DUN (SE) (R2)
LED backlight: 6916L-0913A, 6916L-0882A, 6637L-0013A
T-CON: 6870C-0401C
LED driver (backlight): KLS-E420DRPHF02C, 6917L-0095C
PWM LED driver: BD9285F
MOSFET LED driver: AOD482, STC2073
Power Supply (PSU): EAX64604501 (1.5) - LGP32-12P
PWM Power: L6599AD (PWM Resonant), HS01G (PFC), FSL106HR (Standby DIP-8)
MOSFET Power: K10A60D, TK7P60V
MainBoard: EAX64664903 (1.0) EBR75149855, SAA35916750, SAA35948814
IC MainBoard: LGE2111A-T8, K4B1G1646G-BCKO, STA3808 WE, AS324M, 25080 BVSIG, TJ3940, LCX244, Z105NP, AP7173
Tuner: TDSN-G301D
Control: AKB73655802; IR EBR74986702, LM35-55, MB32B00, 1BF-3010B
Specifications 42LS3400
LG 42LS3400
General repair guidelines for TV LCD LED
If the TV does not turn on, no control lights are on or blinking, there are no sounds when you turn on, and there is not the slightest sign of operability - the most likely malfunction is in the power module. It is advisable to start the troubleshooting of the power supply module by checking the state of the electrolytic capacitors of the rectifier filters and the mains fuse. Defective capacitors should be replaced. If the mains fuse is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and transistors, which are often found in such a state of breakdown.
Mos-Fet keys used in switching power supplies (SMPS) rarely fail for no reason to look for when checking other circuit elements. Often the breakdown is caused by malfunctions of electrolytic capacitors or semiconductor elements in the primary circuit, or by a break in the resistors in the stabilization circuits. The PWM controller chip L6599AD, HS01G, FCL106HR can also cause a breakdown of the power switch of the converter.
If there is no image when you turn on the LG 42LS3400, or it appears and immediately disappears, but there is sound, most likely there is a malfunction in the backlight LED circuit of the LC420DUN (SE) (R2) 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.
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. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
In cases of attempts to repair the motherboard EAX64664903 (1.0) EBR75149855, SAA35916750, SAA35948814, it is necessary to check the operation of linear stabilizers and power converters of its microcircuits and, if possible, update the software (software). BGA chips can sometimes be diagnosed with local heating.
In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - LGE2111A-T8, K4B1G1646G-BCKO, STA3808 WE, AS324M, 25080 BVSIG, TJ3940, LCX244, Z105NP, AP7173 with new or obviously working ones. In cases where BGA technologies are used, defects are usually 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 voltages at the terminals of the TDSN-G301D 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.
We recommend the owners of the 42LS3400 TV for repair only to qualified specialists with experience! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!
SCHEMATIC DIAGRAM ----------> LG CHASSIS LT21C; MODEL 32LS3400, 32LS3400-DA
PSU SCHEMATIC DIAGRAM ----------> LGP32-12P EAY62769501 EAX64604501 Power supply
42' ROW Rev0.8 2 R-TYPE 6916L-0913A 42' ROW Rev0.8 2 L-TYPE 6916L-0882A 6637L-0013A
The appearance of the MainBoard EAX64664903 is shown in the figure below:EAX64664903
EAX64664903 can be used in TVs:
LG 32CS460T (Panel LC320WXN (SC)(A4)), LG 42LS3400 (Panel LC420DUN (SE)(R2)), LG 32LS3400 ZC (Panel LC320DXN (SE)(R2)), LG 32LS3500 (Panel LC320EXN (SE)(A2)), LG 32CS466 (Panel LC320WXN (SC)(A4)), LG 32LS3590 32LS3590-ZC.BRUDLJU (Panel T320XVN01.1), LG 32LS359T (Panel LC320EXN (SE)(A2)), LG 42CS460T 42CS460T-ZA (Panel LC420WUE (SC)(A3)).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the EAX64604501 module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the HS01G 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 42LS3400:
Installed matrix (LED-panel) LC420DUN (SE) (R2).
The matrix control uses the Timing Controller (T-CON) 6870C-0401C.
To power the backlight LEDs, the KLS-E420DRPHF02C LED driver is used, controlled by the BD9285F PWM controller. As power elements of the LED driver, keys of the type AOD482, STC2073 are used.
The necessary supply voltages for all nodes of the LG 42LS3400 TV are generated by the EAX64604501 power module or its analogs using L6599AD (PWM Resonant), HS01G (PFC), FSL106HR (Standby DIP-8) microcircuits and power switches of the type K10A60D, TK7P60V.
MainBoard - the main board (motherboard) is an EAX64664903 module using LGE2111A-T8, K4B1G1646G-BCKO, STA3808 WE, AS324M, 25080 BVSIG, TJ3940, LCX244, Z105NP, AP7173 and other chips.
The TDSN-G301D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420DUN-SER2
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 300 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