Technical description and composition of the LG 37LM620S TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 37LM620S
Chassis / Version: LD22E
Panel: LC370EUE (SE) (F2)
LED backlight: 6916L-0828A 7030 6922L-0007A
T-CON: 6870C-0401B
LED driver (backlight): 6917L-0086A PPW-LE37SE-O
Power Supply (PSU): EAX64405901 (1.6) EAY62569601 PSLC-L111A LGP3237H-12P
PWM Power: ICE3BR4765JZ (Standby DIP-7)
MainBoard: EAX64307906 (1.0) EBT62093302
IC MainBoard: LGE2112 1215-BTAH, NAND: KLM2G1HE3F-B001, Sound: STA380BWE
Tuner: TDSN-G351D
Specifications 37LM620S
LG 37LM620S
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 37LM620S TV does not turn on and does not show any signs of operability at all. There is no reaction to the remote control and control buttons from the front panel.
Most likely in this case, the main switching power supply (IIPS) EAX64405901 is faulty. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of the power switches of the converters and rectifier diodes for the presence of a possible short circuit.
In case of any breakdowns 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 more often breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM microcircuits are usually checked by replacement with new ones, or obviously working.
- 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.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. 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.
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction 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.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX64307906 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 elements LGE2112 1215-BTAH, NAND: KLM2G1HE3F-B001, Sound: STA380BWE requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
If there is no reception of television channels, but the TV works properly from external devices, first of all you need to check the voltage of the TDSN-G351D tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention to users! Self-repair of the LG 37LM620S TV without the appropriate qualifications and necessary experience can lead to its complete non-repairability!
schematic diagram -------------> LG 37LM620S Chassis LD22E
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 37LM620S:
Installed matrix (LED-panel) LC370EUE (SE) (F2).
The matrix control uses the Timing Controller (T-CON) 6870C-0401B.
The LED driver 6917L-0086A is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 37LM620S TV are generated by the EAX64405901 power module or its analogs using ICE3BR4765JZ (Standby DIP-7) microcircuits.
MainBoard - the main board (motherboard) is an EAX64307906 module, using chips LGE2112 1215-BTAH, NAND: KLM2G1HE3F-B001, Sound: STA380BWE and others.
The TDSN-G351D tuner provides television reception and channel tuning.