Technical description and composition of the LG 42LM669T TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LM669T
Chassis / Version: LD22E
Panel: LC420EUG (PE) (F2)
LED backlight: 6920L-0001C, 6916L-0948B, 6916L-0947A
LED driver (backlight): integrated into PSU; 67.2V, 0.78A
PWM LED driver: UC2843BD1 (Step-Up LED), AAT2430AISX, R5F100BCAFP
MOSFET LED driver: STF19NF20, PHT4NQ10LT * 6
Power Supply (PSU): EAX64744201 (1.3), EAY62608902, LGP4247L-12LPB-3P
PWM Power: L6599AD (PWM Resonant), FAN7930BG (PFC), STR-A6059H (Standby)
MOSFET Power: STF13NM60N * 2, STF10NM60N * 2
MainBoard: EAX64307906 - EBR75226848
IC MainBoard: CPU: LGE2112 1215-BTAH, NAND: KLM2G1HE3F-B001, Sound: STA380BWE
Tuner: TDSN-G351D
Control: Radio remote control: AN-MR3005; IR: AKB73655833; Wi-Fi: TWFM-B003D, EAT61613401 and IR LM66_76_96 Ver1.6, EBR74986601; Bluetooth: EBR74561201, IA5525-00, BM-LDS302
Specifications 42LM669T
LG 42LM669T
General repair guidelines for TV LCD LED
In the case when the 42LM669T does not turn on, does not respond to the remote control and buttons on the front panel, does not blink bulbs and does not show any signs of operability, the EAX64744201 (1.3), EAY62608902, LGP4247L-12LPB-3P power supply module is probably defective. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is broken 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.
Power switches in pulsed power supplies (SMPS) fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The cause may be a malfunction of the PWM controller chip, which can only be checked by replacing it with a new or obviously working one.
If the LG 42LM669T has no image, but there is sound and the TV is controlled by the remote control, a malfunction in the backlight circuits of the LC420EUG (PE) panel (F2) is likely. LEDs or their power converter - LED driver may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the backlight assembly.
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.
To open all transitions, several tens of volts or more are necessary, and it is best to use a current source for such purposes. A break in the line of LEDs connected in series cannot be detected with a multimeter or tester without disassembling the panel. In the open panel, it is necessary to check each LED. If your multimeter cannot open the LED transitions in forward bias, then see the presence of the PN transition of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
On the motherboard EAX64307906 - EBR75226848, in case of a malfunction, you should first check the performance of all the stabilizers and power converters of the microcircuits, and also, if necessary, update the software (software).
In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - PU: LGE2112 1215-BTAH, NAND: KLM2G1HE3F-B001, Sound: STA380BWE with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
Before changing the TDSN-G351D 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 and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
It should be remembered! Attempts to repair the LG 42LM669T 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 DIAGRAM ----------> LG CHASSIS LD22E; MODEL 42LM660S, 42LM660T, 42LM669S, 42LM669T, 42LM660S/660T-ZA 42LM669S/669T-ZC.
PSU SCHEMATIC DIAGRAM ----------> LGP4247L-12LPB-3P - EAY62608902 - PLDF-L103B - EAX64744201 (1.3 - 1.5).
Led cool: 6922L-0023A 401;
42 ART TV REV 0.4 1 L-Type 6920L-0001C 6916L-0948B;
42 ART TV REV 0.4 1 R-Type 6920L-0001C 6916L-0947A.
To reduce the backlight current in LED drivers with the AAT2430AISX controller, increase the resistance of the resistor from terminal 50 (ISET) to the housing, for example, from 3 KOhm to 4.7 KOhm. Currents will proportionally decrease in each of the 16 channels. With a parallel connection of channels, currents are summed
The appearance of the MainBoard EAX64307906 is shown in the figure below:EAX64307906
EAX64307906 can be used in TVs:
LG 32LM640T ZA (Panel LC320EUA PE F2), LG 32LS570T (Panel LC320EUN (SE) (M2)), LG 47LM620S (Panel LC470EUE (SE) (F4)), LG 42LM670T (Panel LC420EUG (PE) (F2)), LG 42LM640T 42LM640S (Panel LC420EUG (PE) (F1)), LG 42LM620T (Panel LC420EUE (SE) (F1)), LG 47LM660T (Panel LC470EUG (PE) (F1)), LG 42LS570T (Panel T420HVN01.0), LG 42LS570S ZB (Panel LC420EUE (SE) (M1)), LG 42LM669T (Panel LC420EUG (PE) (F2)), LG 42LM669S (Panel LC420EUG (PE) (F1)), LG 37LM620T (Panel LC370EUN (SE) (F2)) , LG 47LM669 (Panel LC470EUG (PE) (F2)), LG 32LS570S ZB (Panel LC320EUN (SE) (M2)), LG 47LM620T (Panel LC470EUE (SE) (F3)), LG 47LM761T ZA (Panel LC470EUH (PE) (F1), LG 32LM620S (Panel LC320EUN (SE) (F2)), LG 47LM670T 47LM670T-ZA.BRUWLJU (Panel LC470EUG (PE) (F1)), LG 42LM660S 42LM660S-ZA.BRUWLJU (Panel LC420EUG (PE) )), LG 42LM660T 42LM660T-ZA.BRUWLJU (Panel LC420EUG (PE) (F1)), LG 32LM620T (Panel LC320EUN (SE) (F3)), LG 55LM620T 55LM620T-ZE (Panel LC550EUE (SE) (F1)).
PSU Advanced
The 42LM669T is equipped with an EAX64744201 power supply module using the PFC (Power Factor Correction) scheme, which acts as an active filter to eliminate the higher harmonic components of the current consumption. The boost converter based on the FAN7930BG PWM controller does not allow the input rectifier filter's electrolytic capacitor to be connected to the network directly through open diodes when the charge current determines its reactance (about 15-30 ohms at a frequency of 50 Hz). As a result of the conversion, the charging current of the capacitor will be determined in such a way that the envelope of the high-frequency pulses of the input current will repeat the phase and shape of the sine wave of the input voltage. The health check of the PFC unit is carried out by measuring the DC voltage on the capacitor of the rectifier network. In operating mode, it should be around 380V, in standby approximately 300V.
The appearance of the power supply
Main features of the device LG 42LM669T:
Installed matrix (LED-panel) LC420EUG (PE) (F2).
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller UC2843BD1 (Step-Up LED), AAT2430AISX, R5F100BCAFP. As power elements of the LED driver, keys of the type STF19NF20, PHT4NQ10LT * 6 are used.
The necessary supply voltages for all nodes of the LG 42LM669T TV are generated by the EAX64744201 power supply module or its analogs using L6599AD (PWM Resonant), FAN7930BG (PFC), STR-A6059H (Standby) microcircuits and power switches of the STF13NM60N * 2, STF10NM60N * 2 type.
MainBoard - the main board (motherboard) is an EAX64307906 module, using CPU chips: LGE2112 1215-BTAH, NAND: KLM2G1HE3F-B001, Sound: STA380BWE and others.
The TDSN-G351D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUG-PEF2
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 360 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 1.06B (8-bit + FRC), CIE1931 68%
Response Time: 6/8 (Tr / Td)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: EPI, 100 pins
Voltage: 12.0V