Super Weird iMac Problem.

[Mars478]

One of the iMacs in my computer lab has been acting up. It keeps trying to start... but does not. It restarts over and over. I've tried everything. PMU, OF, Safe, etc, etc.
I've even replaced the Power supply... which leads me to believe that the mother board is at fault.
Video of the machine...

Thank you.
It is a 2.4ghz model 20" I believe.

 

[pdubak]

It's not the motherboard, its the logicboard.

Seriously though, i'm postive thats your problem.

 

[Hellhammer]

It's not the motherboard, its the logicboard.

Seriously though, i'm postive thats your problem.

That's same thing, Macs' mother boards are just called logic boards

http://guides.macrumors.com/Mac_doesn't_boot

 

[MacHamster68]

dont worry as i see in the video two nice cool fantastic g3 clamshells 's
you will always will have them as backup ...who needs a imac if you got ibook clamshell g3's


and yes its the logic board , no doubt about that