Do you have an early model (233mhz) iMac that shuts down seconds after pressing the power button? Was it preceded by a flickering screen and a crackling sound? These can be the symptoms of a dead or dying Flyback Transformer. It is very common in these iMacs and is caused by excessive heat around the transformer. Once the Flyback Transformer burns out the iMac will refuse to start up. Generally, it will shutdown one or two seconds after you press the startup button. This is because the iMac detects a problem with the video and shuts itself down. There is a simple test you can do to see if it is the Flyback Transformer.

The Test:

- Unplug all the cables to the iMac and turn it over and remove the bottom cover.

- Then loosen the two screws that secure the video cable and disconnect it.

- Plug the power cord back in and try to startup the iMac with the video cable disconnected.

- Listen carefully to the iMac. Does it sound like it is starting up? Do you hear the normal startup   sounds? Or does it just shut down on its own? If it sounds like it's starting up, then your Flyback     Transformer is the culprit. If it continues to shut down immediately, then you have some other   problem.

The Flyback Transformer can be fixed but it's a $200 to $300 repair and probably more than the computer is worth. You can repair it yourself but it is only for people who have a good knowledge of electricity and know how to work around very high voltages. However, there a couple of solutions.
1 -This is a simple but somewhat clunky solution. You can buy another computer monitor and plug it into the video port on the bottom of the dead iMac. Any Mac or VGA monitor will work fine. If it's not a Mac specific monitor you'll have to buy a Mac to VGA adapter. They generally cost less than $10 and can be found at any store that sells Mac stuff. You can pick up a new or used monitor for under $100. To plug an external monitor into your iMac all you have to do is unplug all the cables, turn the iMac over and remove the remove the bottom cover. Then unplug the video cable and move it to one side. Plug the new monitor (via a Mac to VGA adapter if necessary) into the video port, then turn the iMac back over and plug everything back in. You'll have to leave the bottom cover off because there is nowhere to pass the new monitors cable through it. You could cut a notch in it with a hacksaw but it's not a big deal to leave it off completely.
2-The main drawback to the first setup is that you'll need to have both monitors on your desk at the same time. If you don't use the CD-ROM, you can put the iMac on the floor and just have the new monitor on your desk. Or you could try another more radical solution. I've made it into a seperate page because it's more complicated than the first solution but the end result is very good. I've done this with my old iMac and I've very pleased with how it worked out.

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