iMac Graphite Power-on Problem

I'm currently repairing an old Graphite iMac, and I've run into a brick wall with the thing. It will not power on. When you press the power button, you'll hear the CRT crackle for a moment, like it's going to come on, the power light will flash on once, then go off and the iMac will not power on. I've replaced the dead Tandium battery, and even replaced the power supply board, but so far to no avail. I can't seem to figure out what's causing this.

Is it the Video circuitry for the CRT?
Is it the CRT itself?
Main Logic Board?
Has anyone else encountered such a problem before?
Were you able to resolve it and if so, what was the fix?

Thanks in advance for any advice you can offer.

Does the CPU power up? or is it both the monitor and CPu that don't power on.

Graphite said:

Does the CPU power up? or is it both the monitor and CPu that don't power on.

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Neither will power on. The power light flashes once, you hear the crackle of static like the CRT makes when it gets that first zap of power, and then nothing. You can push the power button again and the same thing repeats, but nothing will power on.

Bumping this thread to see if anyone knows what I should look for. The iMac is still on our workbench and I don't want to keep the customer waiting for too long. Any ideas?

so you run a buisness repairing computers and you dont know how to fix them?

Yeah, are you going to pay us for our time?

MacMania55 said:

so you run a buisness repairing computers and you dont know how to fix them?

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Normally, I can, but this one is a bit beyond me. Plus, the vast majority of computer repairs we do are Windows boxes, NOT Macs. I am the 'Mac Specialist' here, and in 5 years of working here, I rarely ever see a Mac come in with problems. Usually it's a software issue, or an upgrade (Bigger hard disk, more ram, upgraded CD/DVD/Burner, etc..). This is only the second hardware issue I've seen come in, and the first one of it's kind. So please understand, I've done everything I can think of, even ordered in a replacement power supply thinking that might work, and it's still not powering on. Instead of wasting money and a ton of time trying to figure this out the hard way (and possibly failing) I come to my fellow Mac community for help. Perhaps someone has run across this issue before and can offer a suggestion I haven't thought of? I'm looking for a serious answer here, not jokes, jabs or sarcasm. This customer loves her iMac, and is being extremely patient waiting for it to be fixed. I want to help her, but I'm admittedly at the end of my experience and knowledge with this type of problem. I've researched this as far as I can online. I don't know where else to turn to for information on this, except to the Mac Community-at-large.

I've worked with these imac before.. what it sounds like the problem is the analog board ( video board)... The crackle is the flyback transformer shorted out from the transformer going bad. The imac g3's had poor ventallation, and over time, the flyback transoformers over heated. Because of the short, the computer will turn itself off to protect the rest of the system. replace the analog board and the computer should be good to go!

that would be $10 for a counsoltation fee

just kidding! Hope this helps!