External Monitor goes black for few seconds

[leopetr95]

Hi everyone, I have an external monitor connected to my laptop. The problem is that very often the external screen goes black for few seconds. Consider that the problem occurs with both windows and ubuntu and that my laptop has an HDMI port and a usb C- display port. Here is what I tried to solve the problem without any result:

• Tried every resolution and refresh rate and every combination of these
• Uninstalled drivers of the integrated and discrete graphics card, also with DDU
• Disabled both the integrated and discrete graphics card
• BIOS updated
• Drivers Updated
• Tried different cables on all the ports of the monitor
• Tried different monitors
• Removed the battery and run without it
• Tried without current
• Thermal paste replaced on both CPU and GPU
• Tried different hard drives
• Tried every power management configuration
• Used my monitor with a nintendo switch and a chromecast without the issue

Furthermore I am not able to reproduce the issue, it seems to appear very randomly, I also run some benchmarks to test every single component and it seems there is no correlation with temperature or utilization or fan speed. Other 2 details that I noticed:

• When the notebook is connected via usbC-display port, the monitor also flickers before going black and sometimes the monitor loses signal completely
• I connected my laptop to a TV and the problem seems not to appear

Can anyone help me? Thank you very much in advance