SOLVED Instable raspberry when display connected

[selyjohns]

Hi,
I’m under construction of my first MM.
It’s very good software.

From the scratch, i’m only work on the rpi with no display connected. All was good.

Today, i’ve plug the display (hdmi > hdmi vga adaptator > VGA monitor)

When the display is conneted, my rpi is not stable anymore. The latency is very important, the rpi drop 80% of ping. There is no internet connection so most of modules are not functionning.

I’ve tested with officiel alimentation of RPI.
I’ve tested with MeanWell RS-15-5, same result…

Do you know why and if there is a solution ?
Thank you guys.

[selyjohns]

Solved !
After multiples tests, the problem was the raspberry has CPU overload when hdmi plugged.
I’ve deduce this with this test : disable the remotecontrol module, that need a lot of CPU to works, and it was better.

So, I’ve tried to modify some parameters on /boot/config.txt, and the good one was to define manually the hdmi_group and hdmi_mode

My display is old vga screen 1680x1050 60Hz

So, according to the documentation, the good parameters is
hdmi_group=2
hdmi_mode=58

But, result was the same. So I’ve tested with reduced blanking mode
hdmi_group=2
hdmi_mode=57

And now all works great
Have a nice day.