Just a guess but this might be related to the issue #65887. My monitor goes off after 1200 seconds when I use the command "xset dpms 0 0 1200". KDE's power saving settings are not used, though. Check #65887.
-- Display does not enter power-save (both tty1 & X) https://launchpad.net/bugs/66026 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
