Technical description and composition of the LG 32LB552U TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 32LB552U
Chassis / Version: LC43B, LD43B, LB43T
Panel: NC320DXN-VSBP4
T-CON: 6870C-0565AC, PWBX5409TP ZD
LED driver (backlight): integrated into PSU; 117V, 250mA
PWM LED driver: SSC1S311, A27RAE (sot23-6)
MOSFET LED driver: STD11N65M5, STN4NF20L
Power Supply (PSU): LGP32-14PL1 EAX65391401 (3.0) REV3.1
PWM Power: NCP1251, NR134S
MainBoard: EAX65388006 (1.0)
IC MainBoard: LGE2131, H27U1G8F2CTR, 25L8006E, H5TQ1G63EFR
Tuner: TDJM-G101D
Control: AKB73715679, IR: EBR78925201
Specifications 32LB552U
LG 32LB552U
General repair guidelines for TV LCD LED
Possible manifestations of defects
- LG 32LB552U does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons on the front panel.
A malfunction in such cases is detected in the LGP32-14PL1 power supply module. It is necessary to verify the presence of supply voltages at its outputs and, in case of their complete absence, check the power switches and rectifier diodes of the converter for a probable short circuit.
During thermal and avalanche breakdowns of semiconductors in secondary circuits, the converter can usually work normally in emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and less often the current sensor at the source of the key.
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 an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may also be PWM (PWM) NCP1251. It is checked by replacing it with a new or obviously working one.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
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.
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.
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the EAX65388006 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 - LGE2131, H27U1G8F2CTR, 25L8006E, H5TQ1G63EFR 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.
If the TV works normally from external devices, but does not tune into television channels, the TDJM-G101D may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention to users! Self-repair of the LG 32LB552U TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
Service manual and schematic diagram----------------------->LG CHASSIS: LD43B/LD44B MODEL: 32LB55** 32LB55**-Z*, 32LB552U, 32LB552U-TB
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 EAX65388006 is shown in the figure below:EAX65388006
EAX65388006 can be used in TVs:
LG 32LB561V (Panel LC320DUE), LG 32LB561U (Panel NC320DXN VSBP1), LG 42LB629V ZM (Panel LC420DUE (FG)(P2) ), LG 32LB563U (Panel NC320DXN VSBP1), LG 42LB552V ZA (Panel LC420DUE (FG)(A6)), LG 32LB552U (Panel NC320DXN-VSBP4), LG 32LB563V (Panel LC320DUE (FG)(A3)), LG 42LB561V ZE (Panel LC420DUE (FG)(A3)), LG 42LB569V 42LB569V-ZX.BRUWLDU (Panel LC420DUE (FG)(A3)).
The appearance of the power supply
Main features of the device LG 32LB552U:
Installed matrix (LED-panel) NC320DXN-VSBP4.
The matrix control uses the Timing Controller (T-CON) 6870C-0565AC.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller SSC1S311, A27RAE (sot23-6). As power elements of the LED driver, keys of the type STD11N65M5, STN4NF20L are used.
The necessary supply voltages for all nodes of the LG 32LB552U TV are generated by the LGP32-14PL1 power module, or its analogs using NCP1251, NR134S microcircuits.
MainBoard - the main board (motherboard) is an EAX65388006 module, using LGE2131, H27U1G8F2CTR, 25L8006E, H5TQ1G63EFR and other chips.
The TDJM-G101D tuner provides television reception and channel tuning.