Sunday 23 February 2020

REPAIR / SERVICING TV LG 39LA620V

Technical description and composition of the LG 39LA620V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 39LA620V ZA
Chassis / Version: LD33B
Panel: T390HVJ01.0
LED backlight: LG lnnotek POLA2.0 39 A / B Type Rev00
T-CON: 42T27-C0C T420HVD02.2 CTRL BD
LED driver (backlight): integrated into PSU; 157V 341mA
PWM LED driver: MAP3202
MOSFET LED driver: FDT86106, STF10NM60N
Power Supply (PSU): EAX64905301 (2.4)
PWM Power: SSC1S311A (PWM flyback), NR891D (PWM Step-down 24/12)
MOSFET Power: MDF11N65B
MainBoard: EAX64797003 (1.2) - EBR76823186 0641
IC MainBoard: CPU: LGE2122, NAND: SAA36403538 VER. 3.20.33 H5TQ4G63AFR x2 H5TQ2G63AFR NTP7513
Tuner: TDSQ-G601D (B)
Control: AKB73756502, IR: EBR77031901
Specifications 39LA620V
LG 39LA620V
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 39LA620V TV does not turn on. There are no signs of operability. The indicators on the front panel do not shine and do not blink, and the remote control and control buttons do not respond.
Most likely in this case, the EAX64905301 power module is faulty. It is necessary to measure the secondary output voltage, and in case of their absence, check the serviceability of the power switches (MDF11N65B) of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse 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. PWM chip SSC1S311A (PWM flyback), NR891D (PWM Step-down 24/12) can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX64797003 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: LGE2122, NAND: SAA36403538 VER. 3.20.33 H5TQ4G63AFR x2 H5TQ2G63AFR NTP7513 requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
In cases where there is no 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 voltage at the terminals of the TDSQ-G601D (B) 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.
Attention! For users and owners of 39LA620V TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.


schematic diagram -------------> LG CHASSIS LD33B; MODEL 39LA62** 39LA62**-Z*.

schematic diagram PSU ----->  LG 37/39/42 Inch LGP3739-13PL1, LGP42-13PL1.

LED: LG lnnotek POLA2.0 39 A Type Rev00
LG lnnotek POLA2.0 39 B Type Rev00


 The appearance of the MainBoard EAX64797003 is shown in the figure below:
EAX64797003
EAX64797003 can be used in TVs:
LG 42LA620V (Panel LC420DUE (SF)(U1)), LG 32LN570V (Panel LC320DUE (SF)(R1)), LG 50LA644V (Panel LC500EUN (SF)(F1)), LG 47LA660V (Panel LC470EUG (PF)(F1)), LG 47LA621V (Panel LC470DUE (SF)(U1)), LG 42LA644V (Panel LC420EUN (SF)(F2)), LG 39LA620V ZA (Panel T390HVJ01.0), LG 42LA621V ZD (Panel LC420DUE (SF)(U1)), LG 32LA621V ZD (Panel LC320DUE (SF)(U1)), LG 32LN655V (Panel LC320EUB (PF)(M1)), LG 42LA667V (Panel LC420EUH (PF)(P1) ), LG 47LN613V (Panel LC470DUE (SF)(R4)), LG 32LA667V ZB (Panel LC320EUB (PF)(P1)), LG 55LA660V ZA (Panel LC550EUH (PF)(P1)), LG 47LA620V ZA (Panel LC470DUE (SF)(U1)), LG 32LN613V ZB (Panel LC320DUE (SF)(R4)), LG 42LN655V ZB.BRUZLJU (Panel LC420EUH (PF)(M1)), LG 32LA644V ZA (Panel LC320EUN (SF)(F1)), LG 42LN613V (Panel LC420DUE (SF)(R4)), LG 47LA690V ZB (Panel LC47EUH (PF)(P1)), LG 47LA662V (Panel LC470EUG (PF)(F1)), LG 42LA645V 42LA645V-ZC.BRUYLJU (Panel LC420EUN (SF)(F3)), LG 32LA660V (Panel LC320EUB (PF)(P1)), LG 47LA644V 47LA644V-ZA (Panel LC470EUN (SF)(F2)), LG 50LA667S (Panel T500HVD02.1), LG 47LA691V (Panel LC470EUH (PF)(P1)), LG 32LA662V (Panel LC320EUB (PF)(P1)).
The appearance of the power supply
Main features of the device LG 39LA620V:
Installed matrix (LED panel) T390HVJ01.0.
The matrix control uses the Timing Controller (T-CON) 42T27-C0C.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the MAP3202 PWM controller. 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 39LA620V 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 EAX64797003 module using CPU chips: LGE2122, NAND: SAA36403538 VER. 3.20.33 H5TQ4G63AFR x2 H5TQ2G63AFR NTP7513 and others.
The TDSQ-G601D (B) tuner allows you to receive television programs and tune to channels.