LG 29EA93 - No video

[Tom83_Elec]

Hello!,

i've here a LG29EA93 monitor that no longer shows a video signal.
The strange thing is that the menu is working without any problem. I can make settings, switch input source, reset to factory and so on. Fully functional except the input video signal. I've tested all sources - all with the same issue.
When i connect it to a pc the monitor is correctly recognized (name, resolution), the monitor shows "No signal" and go to "energy saving mode". After shutdown it turns on immediately and shows "No signal" again. This is a endless loop "No Signal" -> "Energy saving" -> Turn On
I've already cleared the NVRAM via service mode menu. The monitor also displays "EDID OK" for all input sources - So i think the EDID EEPROMs should be also fine.
I've also tested all DC-DC converters on the board - All voltages are fine.
The logic board has a TUSB3410 USB to UART chip that is directly connected to the video scaler (STDP9320). I tried to listen to it but got no data (Debug mode in the service menu was activated) Perhaps i do it wrong..

Now I am rather at a loss.
Maybe someone can help me? :-)