Technical description and composition of the LG 42LB658V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LB658V
Chassis / Version: LD42B
Panel: LC420DUH (FG) (P2)
LED backlight: 42 DRT3.0 REV7 2 A / B-Type 1SB-0395/0396
T-CON: 6870S-1734A, 6870S-1735A.
LED driver (backlight): integrated into PSU; 208V 250mA
PWM LED driver: BD9486F
MOSFET LED driver: MDD3752, 4NF20
Power Supply (PSU): EAX65423701 (2.1) LGP3942-14PL1
PWM Power: MAP8800 (PFC), FA6A01N (PWM resonant), NR134S
MainBoard: EAX65384004 (1.5) DY40121200
IC MainBoard: CPU: LG1311; DRAM: H5TQ4G63AFR-PBC; EEPROM: AT24C256C, EMMC: THGBMAG6A2JBAI
Tuner: TDJM-G101D
Control: AKB73756565, Wi-Fi: 2703H-LGSBW41
Specifications 42LB658V
LG 42LB658V
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 42LB658V TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
Most often, with such manifestations, the main power supply module EAX65423701 is found to be faulty. It is necessary to measure the secondary output supply voltage, and in case of their absence, check the serviceability of the power switches of the converters (PFC and the main source), as well as rectifier diodes for the probability of breakdown in PN junctions.
In case of breakdowns of the diodes in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key 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.
Chips of PWM controllers (PWM) MAP8800 (PFC), FA6A01N (PWM resonant), NR134S can also cause power key malfunctions and are checked by replacement.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
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. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX65384004 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). In some cases, to repair the MB board (SSB), it may be necessary to replace the chips - CPU: LG1311; DRAM: H5TQ4G63AFR-PBC; EEPROM: AT24C256C, EMMC: THGBMAG6A2JBAI for new or obviously working. In cases where BGA technologies are used, defects are usually localized by the heating method.
Malfunction of the tuner TDJM-G101D is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Attention! For users and owners of 42LB658V TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-serviceability of the device.
schematic diagram ------------> LG CHASSIS LD42B MODEL: 42LB65** 42LB65**-Z*.
User Manual WiFi ------------> LG Wi-Fi Module LGSBW41
Backlight Current Limit:
In televisions with power supplies LGP3942-14PL1 (EAX65423701), the backlight current sensor - the resistor block R811-R818 consists of four pairs of 4.3 Ohm each. You can reduce the backlight current by 25% by removing one pair of resistors.
More details on this page
The appearance of the MainBoard EAX65384004 is shown in the figure below:EAX65384004
EAX65384004 can be used in TVs:
LG 32LB650V ZE (Panel LC320DUH (FG)(P2)), LG 47LB650V ZE (Panel LC470DUH (FG) (P2)), LG 42LB650V (Panel LC420DUH (FG)(P2)), LG 42LB671V ZF (Panel LC420DUH (PG) (F1)), LG 47LB671V (Panel LC470DUH (PG)(F1)), LG 42LB653V ZK (Panel LC420DUH (FG)(P1)), LG 42LB720V (Panel LC420DUH (PG)(F1)), LG 42LB658V (Panel LC420DUH (FG)(P2)), LG 47LB677V (Panel LC470DUH (FG)(F1)), LG 42LB679V (Panel LC420DUH (PG)(F1)), LG 47LB653V (Panel LC470DUH (FG)(P1)), LG 32LB653V (Panel LC320DUH( FG)(P1)), LG 42LB690V (Panel LC420DUH (PG)(F1)), LG 55LB630V (Panel LC550DUH).
The appearance of the power supply
Main features of the device LG 42LB658V:
Installed matrix (LED-panel) LC420DUH (FG) (P2).
The matrix control uses the Timing Controller (T-CON) 6870S-1734A.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the BD9486F PWM controller. As power elements of the LED driver, keys of the MDD3752, 4NF20 type are used.
The necessary supply voltages for all nodes of the LG 42LB658V TV are generated by the EAX65423701 power supply module, or its analogs using MAP8800 (PFC), FA6A01N (PWM resonant), NR134S microcircuits.
MainBoard - the main board (motherboard) is an EAX65384004 module, using CPU chips: LG1311; DRAM: H5TQ4G63AFR-PBC; EEPROM: AT24C256C, EMMC: THGBMAG6A2JBAI and others.
The TDJM-G101D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420DUH-FGP2
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 (2H)
Brightness: 300 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6/8 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: EPI, 100 pins
Voltage: 12.0V