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Nie, dziękuję Przekieruj mnie tamI'm looking for the schematics of the PSU used in the TV LG 32LB561B. The LED voltage output
is only 50V
For the LG 32LB561B, the PSU/backlight supply is normally the LGP32-14PL1, with PCB number typically EAX65391401 — revisions such as 2.8, 3.0 or Rev 3.1 are seen in this family. The schematic is commonly listed as:
lg_eax65391401_lgp32-14pl1_psu_sch.pdf
It is available on repair-schematic repositories such as Electronica-PT, eServiceInfo, Club de Diagramas and similar TV repair databases. Electronica-PT specifically lists “LG EAX65391401 (3.0), LGP32-14PL1 Rev3.1” as PSU Schematics. (electronica-pt.com)
However, your symptom — LED output only around 50 V — often does not mean the PSU is bad. On this LG PSU, 50 V is commonly the pre-boost / standby backlight rail. If the LED driver starts, detects an open LED string, and then shuts down, the voltage collapses back to about 50 V. In many cases the fault is open-circuit backlight LEDs inside the panel, not the PSU.
For this model family, look on the PSU silkscreen/sticker for one of these markings:
| Item | Likely marking |
|---|---|
| PSU model | LGP32-14PL1 |
| PCB number | EAX65391401 |
| Other related PCB reference | EAX65693102 in some listings |
| Typical revision | Rev 2.8, 3.0, 3.1 |
| LED driver IC | Often MAP3202 / MAP3202SIRH or similar marking |
| TV chassis family | LC43B / related LG 32LB series |
Search databases list LGP32-14PL1 EAX65391401 directly as a repair schematic / PSU schematic entry. (eserviceinfo.com)
Use search terms such as:
lg_eax65391401_lgp32-14pl1_psu_sch.pdf
EAX65391401 LGP32-14PL1 schematic
LG 32LB561B LGP32-14PL1 power supply schematicDo not rely only on the TV model number; LG often used the same PSU across several related 32-inch models.
The backlight section is a boost constant-current LED driver. It does not behave like a fixed-voltage supply.
A simplified operating sequence is:
If the driver detects:
it shuts the boost converter down.
So, 50 V alone is not enough to condemn the PSU.
For a 32-inch LG using this type of backlight arrangement, the working LED voltage is often much higher than 50 V — commonly around 100–140 V, depending on the exact LED strip version and current setting. If you only see 50 V and the backlight never lights, the most likely causes are:
| Observation | Likely cause |
|---|---|
| Voltage briefly jumps above 100 V then falls to 50 V | Open LED strip / open LED bead |
| Voltage remains fixed at 50 V, no spike | BL-ON missing, DIM signal missing, LED driver fault, boost MOSFET/diode issue |
| Voltage rises very high then shuts down | Open LED load or disconnected LED connector |
| Voltage low and pulsing | Driver entering protection, bad electrolytic capacitor, shorted LED, overload |
| No 50 V at all | PSU secondary fault, startup/control issue |
Turn the TV on and shine a strong flashlight at the LCD panel.
If you can faintly see the image/menu:
Main board and panel logic are probably working; backlight system is faulty.
If there is no image, no sound, or no standby function:
The fault may be broader than the LED supply.
Use a DMM rated for at least 250–600 V DC.
Measure preferably across the LED connector, between LED+ and LED−, not randomly to chassis unless the schematic confirms the reference point.
Procedure:
Interpretation:
Brief spike to about 100–140 V, then back to 50 V:
Very strong indication of open LED strip.
No spike, only 50 V:
Check the control signals from the main board:
No LED rail at all:
Investigate the PSU secondary supply and startup circuitry.
The most reliable test is with a dedicated LED tester.
Results:
| LED tester result | Meaning |
|---|---|
| LEDs light normally | PSU backlight driver or control issue |
| Tester voltage rises high and no light | Open LED string |
| Some zones light, some do not | Failed strip or bad connector |
| Very low voltage / tester current limit | Shorted LED or wiring fault |
For this LG series, failed LEDs are very common. If one LED goes open in a series string, the whole backlight string stops and the PSU goes into protection.
The schematic is not usually included in the consumer user manual. It is normally found separately under the PSU board number. Electronica-PT lists LG EAX65391401 (3.0), LGP32-14PL1 Rev3.1 as a downloadable PSU schematic, and other repair databases list the same file name lg_eax65391401_lgp32-14pl1_psu_sch.pdf. (electronica-pt.com)
Also note that some repair listings for the LG 32LB561B identify the TV with LGP32-14PL1 and panel LC320DXE variants, which is consistent with this PSU/backlight architecture. (dvbshd.blogspot.com)
In practical TV repair, replacing the entire PSU for this symptom often does not solve the fault, because the real failure is frequently the LED strip set. Modern repair practice is to test the LED array first before changing the PSU.
On the LGP32-14PL1 family, the LED boost circuit is typically built around:
| Function | Typical component area |
|---|---|
| LED controller | IC801, often MAP3202-family |
| Boost MOSFET | Q801 or nearby |
| Boost diode | D801 or similar |
| LED output capacitors | High-voltage electrolytics, often 160 V / 200 V class |
| Current-sense resistors | Low-ohm resistor bank in LED return path |
| Feedback/protection | LED− sense, OVP divider, current sense |
The LED driver is a constant-current regulator, so it raises or lowers voltage automatically to maintain LED current. Therefore, the measured voltage depends on whether the LED load is connected and healthy.
The LED driver expects current through the LED string. If the LED string is open:
\[ I_{LED} \approx 0 \]
The controller increases duty cycle trying to raise voltage. When the overvoltage or no-current condition is detected, it shuts down. The rail then drops back to the non-boosted level, often around 50 V.
That is why technicians often see:
Power on → LED+ jumps briefly → backlight flashes or does not light → voltage falls to 50 VThis is a classic open-backlight symptom.
This PSU contains dangerous voltages.
If you are not experienced with offline SMPS repair, use an isolation transformer and proper HV-rated probes, or have the PSU/LED strips tested by a TV repair technician.
Look for:
LG EAX65391401 LGP32-14PL1 PSU SCH
LGP32-14PL1 REV3.1 PCB EAX65391401 schematic
lg_eax65391401_lgp32-14pl1_psu_sch.pdfPrioritize the schematic matching your board revision printed on the PCB.
Recommended sequence:
Some technicians also reduce LED current by modifying the current-sense resistor network, but this should only be done if you understand the MAP3202 current-sense circuit and verify the current afterward. An incorrect modification can cause poor brightness, protection trips, or LED/PSU damage.
lg_eax65391401_lgp32-14pl1_psu_sch.pdf.