So by default when booted into X Windows the Raspberry Pi will blank its screen after 10 minutes of inactivity.
This isn’t so good for museum exhibition machines that need to show content all day.
If you google on the topic of raspberry pi screen blanking you get about half a dozen different suggestions to fix it with settings changes in a bunch of different files.
Only one thing worked for me.
The highest ranked answer here disable-screen-blanking-in-x-windows-on-raspbian
Involves editing /etc/X11/xinit/xinitrc
and adding three xset commands
xset s off # don't activate screensaver
xset -dpms # disable DPMS (Energy Star) features.
xset s noblank # don't blank the video device
The trick here is that xset might not be installed.
Try an xset command on the command line to see if xset in installed.
If it’s not installed you can install it with.
sudo apt-get install x11-xserver-utils