Technical description and composition of the LG 32LN540B TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 32LN540B
Chassis / Version: LD36B
Panel: LC320DXE (SF) (R1)
T-CON: 6870C-0452A
LED driver (backlight): integrated into PSU; 70.3V 400mA
PWM LED driver: MAP3202 (MAP3202SIRH)
MOSFET LED driver: FDT86106, AP18N20GH
Power Supply (PSU): EAX64905001 (2.7) - LGP32-13PL1 EAY62810301
PWM Power: SSC1S311A (PWM flyback), NR891D (PWM Step-down 24/12)
MOSFET Power: MDF11N65B
MainBoard: EAX64891403 (1.0)
IC MainBoard: CPU: LGE2121-MS A7MjD43ZC, Flash: MX25L8006E, EEPROM: 4256BRP, NAND Flash: H27U1G8F2CTR
Tuner: TDSS-G501D
Specifications 32LN540B
LG 32LN540B
General repair guidelines for TV LCD LED
LG 32LN540B, like other televisions, it is advisable to start repairing with a careful examination of the external and internal elements and modules. According to some external signs of a change in the state of some elements, it is sometimes possible to make assumptions about the nature of the defect, as well as determine the further direction of the troubleshooting. Carbonized paint on the upper layer of resistors, electrolytic capacitors of rectifier filters swollen after boiling, cracked soldering at the terminals of heating elements or transformers can often suggest the cause of the defect and possible consequences.
If the EAX64905001 power supply module (2.7) fails, the external manifestations may be different, for example, the LG 32LN540B does not turn on at all and there is no indication of the control lights on the front panel. With the same symptoms, the stabilizer (converter) of the power supply to the control processor may be faulty. When diagnosing and repairing the power supply, first of all, replace the swollen filter capacitors of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
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 chip from the manufacturer.
If, when you turn on the TV, the image appears and immediately disappears, or is missing initially when you turn on, but the sound has other functions that work, there is a high probability of a malfunction of the LED driver (LC320DXE (SF) (R1) panel LED backlight power converter). In such cases, the general power module is also subject to verification, in which the electrolytic capacitors of the rectifier filter supplying the LED driver should be checked.
To check the health of the LEDs, as well as contact connections in the ruler circuit, it is necessary to disassemble the panel.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
When trying to repair the motherboard, you should first check the serviceability of linear stabilizers or power converters of microcircuits and, if necessary, update the software (software).
Board repair and replacement of CPU chips: LGE2121-MS A7MjD43ZC, Flash: MX25L8006E, EEPROM: 4256BRP, NAND Flash: H27U1G8F2CTR are made with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
If you suspect a malfunction of the TDSS-G501D tuner, first of all, you need to make sure that the voltage of the varicaps (30-33V) is present on the corresponding output of the tuner, as well as other voltage supplying it.
Remember! Attempts to self-repair by users of the LG 32LN540B TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!
One of the typical failures of the LG 32LN540B often occurs in the LG panel LC320DXE (SF) (R1).
External manifestations: there is no image, the backlight does not work. In most such cases, the LEDs turn out to be malfunctioning, which, when tested, turn out to be either open or with broken internal zener diodes.
LEDs must be replaced, and the maximum current from the driver should be limited to 10-20%.
To reduce the backlight current in TVs with the LGP32-13PL1 power supply unit (EAX64905001), you can increase the resistance of the current sensor, which consists of a set of pairs of low-impedance resistors R822-R829, only 4 pairs of 3.9 + 4.3 Ohm.
Having repaired one pair, we increase the nominal value of the sensor by 25%, which proportionally reduces the current in the LEDs from 400 mA to 300 mA.
More details on this page
SCHEMATIC MANUAL ----------------> LG 32LN54**, 32LN54**-Z*, 32LN536*, 32LN536*-Z* Chassis LD31B/LD36B.
PSU SCHEMATIC -----------------------> LG LGP32-13PL1, LGP32I-13PL1
The appearance of the MainBoard EAX64891403 is shown in the figure below:EAX64891403
EAX64891403 can be used in TVs:
LG 32LN540B (Panel LC320DXE (SF) (R1)), LG 32LN5400 ZA (Panel LC320DUE (SF) (R1)).
The appearance of the power supply
Main features of the device LG 32LN540B:
Installed matrix (LED-panel) LC320DXE (SF) (R1).
The matrix control uses the Timing Controller (T-CON) 6870C-0452A.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the MAP3202 PWM controller (MAP3202SIRH). As power elements of the LED driver, keys of the type FDT86106, AP18N20GH are used.
The necessary supply voltages for all nodes of the LG 32LN540B TV are generated by the EAX64905001 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 EAX64891403 module, using CPU chips: LGE2121-MS A7MjD43ZC, Flash: MX25L8006E, EEPROM: 4256BRP, NAND Flash: H27U1G8F2CTR and others.
The TDSS-G501D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC320DXE-SFR1
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: IPS, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V