When my iMac DV goes to sleep automatically (that is, after a period of idle time as set in the Energy Saver control panel), it never goes into the full sleep "pulse" mode (where the power light pulses yellow on and off). The only way to achieve this pulse mode sleep is by selecting Sleep manually (as from the Finder's Special menu). Why does this happen? I have AppleTalk, file sharing and any applications except the Finder turned off. Please help!