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[A]a[R]o[N] · Apr 27, 2006, 06:30 PM

I just got an iMac G3 400MHz DV Indigo at a garage sale. I wanted to try out a Mac and wanted to see what OS X was like.

I turned on the computer, and all I got was a click like sound from the speakers and a click like sound from what I think was the CRT. The led on the power button does NOT light up. That's all that happens. I can hit the button forever and thats all that will happen.

So I got the service manuals from the web and took it apart and read the section on checking power voltages. I checked the current of the PRAM battery. It registered as 3.63v so the battery is working. Then I hit the reset button for the PMU chip. When this didn't do anything I continued with the voltage tests.
I checked the +5v trickle power, the Down Converter On voltage, and I checked the Power Board Fuse. All are ok.
The service manual says that after all those the next thing could be that the Power/LED switch board is defective.

Could that be it? I don't have any discs for the computer as the seller couldn't find them. I think the computer is on OS 9. I want to try out this Mac so badly.

kick52 · Apr 28, 2006, 07:25 AM

could it be a blown hard drive with a fault in the power management type of thing? try it without the cd drive and hd. also take out ram.

[A]a[R]o[N] · Apr 28, 2006, 10:38 AM

Thanks for the advice, I will try that tonight when I get home from school.

Turks

[A]a[R]o[N] · Apr 28, 2006, 08:26 PM

Ok, I tried taking out the memory, the hd, and the cd drive. The computer will still not turn on. Could the power supply (down converter board) be bad. They are eBay if I need to buy one.

giskard · Apr 28, 2006, 11:27 PM

I recently had my PowerMac run and then not start up at all. You may want to try this link:

http://docs.info.apple.com/article.html?artnum=2238

I would only hear the click of the power button, on an iMac maybe the screen might get juice for a moment. Or not.

Something else to try I suppose?

[A]a[R]o[N] · Apr 29, 2006, 01:49 PM

I had already reset the pmu as indicated by my first post. Oh well.

kick52 · Apr 30, 2006, 03:50 AM

i dont think your imacs insides are the same as mine, but there is a grey cable which you can take out of the logic board which is there just as you take the underside cover off. thats the monitor video cable. try taking out and running it, but if you cant find it, dont bother.

[A]a[R]o[N] · May 4, 2006, 07:06 PM

Well, I finally got a new battery and it did not work. If you think its a gonner I guess I will finally let it go. Unless I should spend 40 bucks for a new down converter/power board.

as2 · May 4, 2006, 07:46 PM

Needs a new logic board. I had the same problem with mine...

Although the insurance think it broke when I moved house, so replaced it with a shiny new 20" iMac!

[A]a[R]o[N] · May 5, 2006, 03:47 PM

Do I have to get the exact same motherboard or can I go up to 500mhz g3 motherboard. Also the 400Mhz motherboards on ebay dont look the same as I have a chip that has a philips logo on it that is quite a large chip and I also have a lucent logo'ed chip. THe motherboards on ebay dont have those and instead have one chip with a silver heatsink on it. (These ships are right above the ram slots). Also, im guessing that the chip that is in mine and on the web, that has a black heatsink on it is the g3 processor?

[A]a[R]o[N] · May 20, 2006, 11:00 AM

I got the new motherboard, it has a 500mhz g3 on it, and it came with a down converter board. I replaced the motherboard in the iMac, and when I went to turn it on, it did the SAME THING it was doing before! I am so pissed. If there is anything else I can do someone let me know. I don't think I want to waste any more money in it, so if I need another part I think I will pass.

This is my last call for help!