Does a power supply have to be either dead or alive, or can it be weak / failing? i am having a screen flicker issue with my intel imac 24" 2.33ghz. after replacing the inverter board and still having flicker problems, but none on external monitor i am starting to be convinced it is the power supply. i will try to keep my story and symptoms short and simple. if i turn down brightness flickering goes away. if i do anything processor intensive, the flickering comes back until "strain" is released. for example, decide to play command and conquer 3, it will start flickering but go away after i shut down game. it doesn't matter which monitor acts as primary. ( if external is primary cnc makes other monitors go black) if i use quicktime to simultaneously play avi movies, flickering increases in frequency as i add more and more. i have even been able to make imac shutdown. if i play a movie and flash an isight pic from photobooth imac shuts down. i should also mention, internal hard drive is not detected, ive been running off an external. however last night internal groaned and came on. even after rebooting a couple times to see if it would remain, but browsing its contents is usually slow as if it needed more juice. i can only assume it TOO is not getting juice it needs. i have already tried the data cable with a known working one. i should also mention i have the paneling and case open with the screen sitting seperate connected only by its 2 connectors, and have gotten a fan control utility, and app to monitor temperatures, so cooling it NOT an issue here. i have also noticed upon bootup when the flickering begins, sometimes the machine will just shutdown unless i leave the internal screen disconnected. i can then "hot plug it" after bootup. maybe coincidence, maybe not, but while playing with it (thru software usage, games,movies etc) i noticed after changing inverter board sometimes the bottom backlight would go out completely while trying to initiate flicker, putting it sleep then waking it brings it back. whooooo. i hope that was short enough. anyway insight, helpful experiences, or comments? i have a multimeter if anyone knows pinout and voltage draws etc. i would love to do some hard testing. i cant afford to throw any more money at this thing.