Tuesday 18 February 2020

REPAIR / SERVICING TV LG 32LH519U

Technical description and composition of the LG 32LH519U TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 32LH519U
Chassis / Version: LD67C
Panel: HC320DXN-VHVS1-214X
LED backlight: 32LH51 HD SSC REV05 150925
T-CON: K5387TP
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3378E
MOSFET LED driver: AOD2922
Power Supply (PSU): Adapter 19V PSAB-L205B
MainBoard: EAX66805906 (1.0)
IC MainBoard: LGE6351, H27U1G8F, MX25L8035E, LCX244, MP2315 (TSOT23-8 Marking: AGCG), DT1803A, SN1406035, NTP7515D
Tuner: TDJA-G301D
Specifications 32LH519U
LG 32LH519U
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 32LH519U TV does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
Failure in such cases should begin to look in the adapter power supply circuits.
The adapter 19V PSAB-L205B can be purchased by the owner of the TV independently and repair is not always advisable. In any case, the simplest typical defects characteristic of most IIP schemes can be easily detected and eliminated after opening. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches and rectifier diodes of the converters for a probable short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke the excess of maximum current or voltage values. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, but there is sound and all the other functions of the TV work. The image sometimes for a second appears immediately after turning on and disappears.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. Often the cause of the malfunction is the lack of current in the LED circuit, for example, an open or short circuit, or a violation of the contact connections of the connectors.
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 a health indicator. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX66805906 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 cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - LGE6351, H27U1G8F, MX25L8035E, LCX244, MP2315 (TSOT23-8 Marking: AGCG), DT1803A, SN1406035, NTP7515D which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
The TDJA-G301D tuner malfunction 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.
TV users and owners need to remember that attempts to self-repair an LG 32LH519U TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!




The appearance of the MainBoard EAX66805906 is shown in the figure below:
EAX66805906
EAX66805906 can be used in TVs:
LG 32LH510U (Panel HC320DXN-VSVS1 - 511X), LG 43LH513V (Panel HC430DUN-SLVX1 - 511X), LG 32LH520U (Panel HC320DXN-ABVS2-5112), LG 43LH520V (Panel LC430DUE (FJ)(A1)), LG 32LH513U LG 32LH513U-ZE (Panel HC320DXN-VHVS1-214X), LG 49LH520V (Panel LC490DUE (FJ)(A1)).
Main features of the device LG 32LH519U:
Installed matrix (LED-panel) HC320DXN-VHVS1-214X.
The matrix control uses the Timing Controller (T-CON) K5387TP.
To power the backlight LEDs, a converter is used, combined with the main board EAX66805906, controlled by the MP3378E PWM controller. As power elements of the LED driver, keys of the AOD2922 type are used.
To power all the internal components of the LG 32LH519U TV, an external adapter type 19V PSAB-L205B is used.
MainBoard - the main board (motherboard) is an EAX66805906 module using LGE6351, H27U1G8F, MX25L8035E, LCX244, MP2315 (TSOT23-8 Marking: AGCG), DT1803A, SN1406035, NTP7515D and others microcircuits.
The TDJA-G301D tuner provides TV reception and channel tuning.