monitor power management

Both of my monitors (at work and home) are capable of power management, and have worked beautifully under other operating systems and (if I recall correctly) under ealier versions of SuSE. I am currently running SuSE 7.1 with the 2.4 kernel and KDE 2.1. I have the power management features enabled in KDE Control Center. Xset also reports that power management is enabled. However, the monitor remains on if after 24 hours of non use!! Has anyone else had similar problems? Is there something that I am missing or have overlooked? Would be grateful for any advice or help. Eddie