This is possibly due to some application repeatedly probing the monitor
for information. Could you take a look at bug 339200 and bug 344554 and
see if you see similarities? Especially, does Xorg.0.log get some lines
added to it every time the screen goes black?
** Summary changed:
- Jaunty: rando
** Attachment added: "Dependencies.txt"
http://launchpadlibrarian.net/24883551/Dependencies.txt
** Attachment added: "LsHal.txt"
http://launchpadlibrarian.net/24883552/LsHal.txt
** Attachment added: "LsMod.txt"
http://launchpadlibrarian.net/24883553/LsMod.txt
** Attachment added: "LsPc