TV is not turning on, standby LED is on without picture and no sound
Needing the tv's electrical scheme

Service manual you can download from our site

DOWNLOAD LG 50PT250B шасси PB11K : LG 50PT250B шасси PB11K.pdf

Here are the links for your question:

Ремонт плазменных телевизоров PDP (Инструкция по проверке PDP TV) LG и др.

Инструкция по ремонту 60 дюймовой PDP LG

Краткое описание PDP LG 42PJ650

Launch the panel offline

On the EAX63529101 board, note the zener diode Z101 is missing on the side of the P2 connector (GNG, GND, NC, VS, VS, NC, ERCOM, ERCOM). This zener does not know its value.
In the p1 connector (flat connection to the CTR board EBR72680701 WL50114A002184) the IC201 chip presented a heating, which for me was abnormal.

Now all the pins of the P1 connector are out of tension.
At the moment I was unable to access the scheme that was made available to me

If you can not download the scheme, write to the chat administrator.

A circuit on the power supply is missing, only there is a service manual and circuit on the mainboard.

To check PDP you need a diagnostic mode.

To enter diagnostic mode, you must disconnect the LVDS cable and power supply board from the main board and close the logic board contacts (Ext_auto_gen and +3.3V).