Wednesday 19 February 2020

REPAIR / SERVICING TV LG 32LM640T

Technical description and composition of the LG 32LM640T TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 32LM640T ZA
Chassis / Version: LD22E
Panel: LC320EUA PE F2 // LC320EUA PE F1
LED backlight: 6922L-0025A, 6920L-0001C
LED driver (backlight): 6917L-0091A KLS-E320DRGH // KLS-E320DRGHF06A
Power Supply (PSU): LGP32M-12P - 3P - EAY62512402 - EAX64744501 (1.3)
PWM Power: 3BR4765J (Standby), L6599AD (PWM Resonant), FAN7930
MainBoard: EAX64307906 (1.0) - EBR75226858
IC MainBoard: LCE2112, H5TQ2G63DFR, KLM2G1HE3F, MICOM R5F100GEA, TPS65178, STA3808WE, 24C16
Tuner: TDSN-G351D
Specifications 32LM640T
LG 32LM640T
General repair guidelines for TV LCD LED
LG 32LM640T, like other televisions, it is advisable to start repairing with a careful examination of the external and internal elements and modules. It often happens that visible damage to elements or connections helps determine the 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.
In the absence of any signs of operability, when the LG 32LM640T does not turn on and does not signal anything with the control lights on the panel, there is a possibility of a malfunction of the power module of the LGP32M-12P-3P TV. With the same manifestations, the power regulator of the control processor on the motherboard may be faulty. When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and the electrolytic capacitors of the filters of the converter secondary rectifiers. In the event of a fuse breaking, the reason should be sought in the power semiconductor elements of the pulse converter of the main power supply. First of all, it is necessary to check the diodes of the bridge of the rectifier of the mains voltage and the power switch (s) of the converter.
In most cases, key breakdowns in switching power supplies (SMPS) do not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM 3BR4765G chip from the manufacturer.
If the LG 32LM640T does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the backlight circuits of the LC320EUA PE F2 panel is likely. The LEDs or the 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 LED driver, and check the LEDs, connecting obviously known good diagnostics.
To check the health of the LEDs, as well as contact connections in the ruler circuit, it is necessary to disassemble the panel.
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 there is no reception of television channels, but the TV works properly from external devices, first of all it is necessary to check the voltage of the varicap tuner TDSN-G351D, which is usually within 30-33V, as well as other supply voltages on the terminals of the tuner.
Remember! Attempts at self-repair by users of the LG 32LM640T TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!


SCHEMATIC MANUAL ----------> LG 32LM640S, 32LM640T, 32LM640S, 32LM640T-ZA Chassis LD22E.

  PSU SCHEMATIC -------------->  LG EAX64604501 (1.5) LGP32M-12P-3 Power supply


 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)(F1)), LG 42LM660T 42LM660T-ZA.BRUWLJU (Panel LC420EUG (PE)(F1) ), LG 32LM620T (Panel LC320EUN (SE)(F3)), LG 55LM620T 55LM620T-ZE (Panel LC550EUE (SE)(F1)).
The appearance of the power supply
Main features of the device LG 32LM640T:
Installed matrix (LED-panel) LC320EUA PE F2 or LC320EUA PE F1.
The LED driver 6917L-0091A is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 32LM640T TV are generated by the LGP32M-12P power module or its analogs using 3BR4765J (Standby), L6599AD (PWM Resonant), FAN7930 microcircuits.
MainBoard - the main board (motherboard) is an EAX64307906 module, using microcircuits LCE2112, H5TQ2G63DFR, KLM2G1HE3F, MICOM R5F100GEA, TPS65178, STA3808WE, 24C16 and others.
The TDSN-G351D tuner provides television reception and channel tuning.