View Full Version : iMac G3 not powering up
Jul 1, 2008, 05:40 AM
I bought an iMac G3 at an auction, it is the Indigo version with 400MHz G3 processor, 10GB HD, hope that's enough to work out which one.
It will simply not boot up at all, when I first got it I switched it on and it done the Apple chime sound, then nothing, no power light at all.
Now if I press the power button, no power light, no screen, nothing, although the screen sounds like it is coming on (the static sound and the degauss coil), no more chime or anything, as well as the CD drive sounds liek its searching for a disc, and the hard drive clicks a couple of times.
I do not have an Apple keyboard or mouse, and am using a standard wireless USB keyboard and an optical wheel USB mouse.
I don't know if it just needs OS9 on it (it says that on the sticker on the bottom) and if that is the only problem.
Any help would be really appreciated as I had one of these before but sold it.
Oh and I pressed the PMU reset button in the RAM flap while it was not connected to any power, and this hasn't done anything.
Jul 1, 2008, 11:24 AM
Bummer! These are really nice little machines, I hate you're having this problem. I'm assuming it has no OS installed at all?
It could be something as simple as needing a new battery or, worst case scenario, the Power Analog Video (PAV) board is shot.
Here's a good thread with links to others threads with similar problems:
Jul 2, 2008, 02:55 AM
I couldn't even guess if it has an OS on it, Mac or Linux, but I took the battery out, and I had it tested....dead, so hopefully thats the only problem, I have managed to get OS9 off a friend, so fingers crossed
Jul 2, 2008, 08:58 AM
Good luck! A mac with those specs can run 10.3 or 10.4 (firewire permitting) very well, just be sure to upgrade your firmware before installing OS X.
Or keep OS 9 and have a spiffy retro mac ;)
Jul 2, 2008, 11:55 AM
Well I've ordered a new battery so it's meant to be here tomorrow, and I've scouted around, and found the iMac Disassembly guide, so I hope to god its only the battery and not a board, but if it works, I'll try grabbing a copy of OSX, although do you install it directly or upgrade through the versions?? :confused:
Jul 3, 2008, 08:49 AM
Once you pop the new battery in and your iMac boots up I'd install OS 9 first and update the firmware to 4.1.9, you can't update to OS X 10.3 or later without it.
You don't have to upgrade through the versions (10.0->10.1->10.2 etc), whatever OS X you have will be fine for installation.
I'm not sure what version of OS X you were able to find, but I'd avoid anything earlier than 10.3 like the plague.
Here's to hoping it's just a wonky battery!
Jul 3, 2008, 09:00 AM
My bet is that it is the power supply in the unit. It is the most common repair problem besides the hard drive.
My iMac battery died many moons ago and it still boots up and I have tiger running on it. I wonder if it has a old style CD RW drive instead of a DVD. Some of the Macs back then would have either a DVD player drive like mine or a CD burner with no DVD support.
If it isn't a hardware problem, the only way to install OS X on it is to use a USB combo drive.
Instead of fixing it, you can probably buy another one for about $100 bucks in excellent condition.
Jul 3, 2008, 09:47 AM
I suspect, since it's a 400mhz Indigo with a 10GB hd, that it only has a cd-rom drive. It should also have Firewire.
Jul 4, 2008, 06:18 AM
Well the battery came yesterday and replaced it, and reset the PMU button, held it in gfor 5-10 secs to make sure, screwed it all back together, and woo-hoo.....its DEAD lol
No change in what it done before, as BornAgainMac said it COULD be a power supply problem, but as I'm usually a PC person, I am not 100% sure how to change the power supply over on an iMac, I know on a PC you just replace the thing....
Or is this just the point where I say sod it, it only cost me GBP £7 at an auction, and throw it away?
If it is a power supply problem, will all the drives still hum and click etc, and the power light is dead....probably just answered my own question.
Jul 4, 2008, 09:08 AM
I don't know how much longer you feel like messing with this, but have you tried booting it upside down? (I know, sounds ridiculous) Sometimes this is a sign of bad soldering on the flyback transformer. Booting it upside down causes the flyback to pull against the circuit board and often corrects the bad soldering.
Of course, if that works, then that means you have to resolder the flyback and you might not want to bother.
Just for giggles, have you tried another power cord? Occam's razor and all that. These G3's are as notorious for the power cords going bad as they are for bad PAV boards.
Jul 4, 2008, 09:25 AM
Jeez, I just typed a lot and didn't say much in that last post.
The power supply for a G3 iMac like yours is the Power Analog Video (PAV) board. These can be replaced (and found on Ebay) but it does take a fair amount of jiggery pokery, including discharging the CRT.
I've found that taking all the good parts of the iMac w/ a bad PAV board (hard drive, logic board, optical drive, memory) and putting them into a disabled (for lack of a better word) iMac with a *good* PAV board is usually more efficient.
If you look on Ebay, there are oodles of good G3 iMac deals, if you're willing to pop in your own hard drive.
If you decided to sod it and toss the Mac, I'd be sure to scavenge it for all viable parts before chucking it in the nearest tech-recycling bin. The hd, logic board, cd-rom, memory, even the speakers and plastic housing (seriously) These can all be sold or donated, so your purchase wasn't a total loss.