Saturday 15 February 2020

REPAIR / SERVICING TV LG 32LB580V

Technical description and composition of the LG 32LB580V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 32LB580V ZB
Chassis / Version: LD46B
Panel: LC320DUE (FG) (A4)
LED driver (backlight): integrated into PSU; 117V, 250mA
PWM LED driver: SSC1S311, A27RAE
MOSFET LED driver: STD11N65M5, MDHT4N20Y
Power Supply (PSU): LGP32-14PL1 EAX65391401
PWM Power: NCP1251 (PWM SOT23-6 5A2R ..), NR134S
MOSFET Power: KP8N65
MainBoard: EAX65610904 (1.0) EBR78668701
IC MainBoard: H5TQ4G63AFR, EEPROM: 24C256, SOUND: Audio: NTP7513
Tuner: TDJM-G101D
Specifications 32LB580V
LG 32LB580V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 32LB580V 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.
With such manifestations, the LGP32-14PL1 power module usually fails. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches (KP8N65) and rectifier diodes for a probable short circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode, or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers NCP1251 (PWM SOT23-6 5A2R ..), NR134S, in the absence of visible damage or frank short-circuit between the terminals, are checked by replacing with new, 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.
In such cases, the most likely malfunction of the LED backlight elements. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the EAX65610904 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). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - H5TQ4G63AFR, EEPROM: 24C256, SOUND: Audio: NTP7513 and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
Malfunction of the tuner TDJM-G101D 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 32LB580V TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!


Service manual and schematic diagram --------------------->  LG 32LB580V Chassis LD46B.
CHASSIS : LD46B; MODEL : 32LB58**, 32LB58**-Z*, 32LB580V, 32LB580V-TA


FIRMWARE EEPROM ----------------->  LG 32LB580V ZB LD46B, Main: EAX65610904 (1.0) EBR78668701, Panel: LC320DUE (FG)(A4)


You can reduce the backlight current in LG TVs with LGP32-14PL1 power supplies (EAX65391401) as follows. The current sensor consists of six resistors R816-R821 connected in parallel - 1 Ohm, 1 Ohm, 1 Ohm, 1 Ohm, 2 Ohm, 8.2 Ohm. The total resistance in this case will be 0.22 Ohm. If you remove one resistor 1 Ohm, the total resistance increases to 0.28 Ohm, the current decreases proportionally from 250 mA to about 190 mA.

More details on this page

 The appearance of the MainBoard EAX65610904 is shown in the figure below:
EAX65610904
EAX65610904 can be used in TVs:
LG 32LB582V ZG (Panel LC320DUE (FG)(A4)), LG 42LB570V (Panel LC420DUE (FG)(A4)), LG 42LB5800 (Panel LC420DUE (P6)(A4)), LG 42LB580V (Panel LC420DUE (FG)(A4)), LG 32LB570U 32LB570U-ZJ (Panel NC320DXN VSBP2), LG 39LB580V (Panel T390HVF02.0 HC390DUN-VCHS1), LG 32LB580V ZB (Panel LC320DUE (FG)(A4)).
The appearance of the power supply
Main features of the device LG 32LB580V:
Installed matrix (LED-panel) LC320DUE (FG) (A4).
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller SSC1S311, A27RAE. As the power elements of the LED driver, keys of the type STD11N65M5, MDHT4N20Y are used.
The necessary supply voltages for all nodes of the LG 32LB580V TV are generated by the LGP32-14PL1 power supply module or its analogs using NCP1251 microcircuits (PWM SOT23-6 5A2R ..), NR134S and KP8N65 type power switches.
MainBoard - the main board (motherboard) is an EAX65610904 module, using H5TQ4G63AFR microcircuits, EEPROM: 24C256, SOUND: Audio: NTP7513 and others.
The TDJM-G101D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC320DUE-FGA4
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 698.4x392.85 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 66%
Response Time: 7 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V