I have an imac here that fails to boot. When you press the power button, it plays the normal start tone. At the point where the monitor would kick on, it shuts itself off. You hear the monitor kick in, and then off it goes. I imagine this would be hardware, most likely something like a power supply. I will be the first to say I am a PC tech who is playing in the Mac, so it's not like I troubleshoot these daily.

What iMac is it? Some are more likely to have PSU failures than others ;) p

It's a 333/32/6g/6v family no m4984 that should narrow it down a bit.

OK, just making sure it was one of the first four revisions. The tray-loaders are rather more prone to PSU failures than the slot-loaders. See if zapping the PRAM has any effect, but I rather doubt it will. p

I'm assuming you have a 400MHz slot-load machine. Try re-setting the PMU chip. To do this, pop open the little memory door on the bottom; you should be able to see the PMU reset button. Unplug the iMac. Wait 10 seconds. Reach in with a long thin screwdriver and press the reset button ONCE. Wait 5 minutes. Plug in the iMac again and try it out. It may also help to wait overnight (I don't know why...) before restarting it. The blinking folder/question mark thing is usually associated with bad HD drivers, which you can find instructions for reloading in your iMac system disks. If you can get the CD drive to read a disk again, start from your iMac CD's and then reload the drivers. I'm assuming the 3.6V battery is OK; you have to pull the EMI cover to do this. Hope this helps a little.......

hi guys, i have the same problem with Imac G3 233MHz. Is it becaus of the PSU? If it is, can you tell me where I can get a new one?

I come across a lot of the early tray load iMacs (Rev. A-D) that fail due to the analogue board (the one that drives the display), one way to check to see if this is the cause of the dead iMac is to remove the bottom cover and plug in an external multisync apple monitor (or a PC monitor using an adaptor), if it powers up and runs, the analogue board has failed. I have been converting these dead iMacs into PC cases, also adding things such as a CD writer, ZIP drive and a second Hard drive ! For more info one how to do it go to my site and click on the "iMac Mods" button in the left frame. http://www.radiomods.co.nz Scott G. The Defpom http://www.radiomods.co.nz