Monitor totally inoperative, has voltages of 5V, 3.3v, 12V but does not present the voltage of 1.8v on pin 2 of U601 and pin 1 there is voltage of 3.3v. At pin 2 the voltage presented there is 5V. In the diagram I have, it does not include the diagram of this part of the circuit.

please, can you place here photo of the PCB?
U601 - LDO or PWM regulator?
Maybe there is short to the ground on 1.8v pin?

The U601 integrated circuit must be defective. It is powered with 5v and provides two output voltages being one of 3.3v and one of 1.8v. Pin 2 is not shorted. It is necessary to find a regulator that supplies 3.3v and 1.8v voltage at the output.

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Posted after 21 minute 57 seconds:
the U601 is PWM regulator . In pin 1 output 3.3v the in pin 2 output 1.8v.

I removed the U601 (APE8839mp) from the video card and tested using an external 5v source, obtaining the correct 3.3v and 1.8V voltages.

I was analyzing the video card better and compared to the monitor scheme, I found two smd resistors that
, Whether it exists or not. It would be the resistor R744 and R745 that on the board they do not contain them and, in the schematic, it is written as "Ready".


R744 ->? Does he exist or not?
R745 ->? Does he exist or not?

where I can get the latest firmware version of LG W1953TE monitor, should be to : 1.7.2

Many thanks for the help of the colleagues but since I knew the problem is on the video card and the client was in a hurry I ended up swapping the video card. After replacing the video card, the monitor returned to normal operation.