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Acer V223HQ - ILPI-075 Rev.A power supply turns off

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Block3r picture

I'm sorry for writing in English, but I don't understand any single word in Hungarian and I couldn't find an English subforum there.
I have changed the LVDS controller and now it's working perfectly, but I need help with the backlight. The CCFL lamps in the screen are OK. I connected the screen to another inverter (from BenQ T705, made on TL1451 which also has "protect" function) and the backlight worked perfectly. Again, I connected other screen to the malfunctioning ILPI-075 inverter and the screen also goes blank.
I changed all THT electrolytic capacitors on the board, but not much has changed. Before, the backlight was turning off almost immediately, now it glows for 1-2 seconds and then turns off.
The HV side of inverter transformers is about 470 ohm, they look OK.
I measured random capacitor in the +16V line, which is supplying the high voltage inverters.

We can see how the voltage went down while the backlight was powered on.
Also, the ON/OFF signal on ICL837's pin 8 is always present after powering up the power supply, even after the backlight turns off.
I don't have any idea what to check now..