Going into system settings>power management>energy saving settings, dim display and screen energy saving are both unchecked, however, the monitor always turns off after one minute. I have to check, hit apply, then uncheck and hit apply again to get it to stop, but then it just happens again at next bootup.
This also happens to me, but longer than one minute; mine is more like maybe 10 minutes. I'm using the work-around of setting the monitor blank and dim to the highest possible setting of 360 minutes.
Here is a whole thread about this issue :: http://www.kubuntuforums.net/showthread.php?58993-DPMS-Turns-Itself-On
Also effects me using KDE 4.9.2 on Kubuntu 12.10.
You shouldn't need workarounds any more, with 4.9.3 or later.
*** This bug has been marked as a duplicate of bug 295164 ***