Help me decide what to do with dead iMac G3

Discussion in 'PowerPC Macs' started by Borjan, Jan 22, 2006.

  1. Borjan macrumors regular

    Sep 28, 2004
    Hi there.

    Basically, I managed to get ahold of an iMac G3 a while ago. A 500mhz Graphite model, came with no hard drive, or ram, or PRAM battery, but I got it for £30, so I reckoned that maybe it might be worth it.

    Hopefully, I thought, I would be able to get it working.

    No luck so far.

    I managed to get a PRAM battery for like £5.

    Put that in.

    Had a 40Gb IDE hard drive lying around.

    Put that in too.

    Had a random stick of memory lying around, don't know what size, but it was the right type, so...

    Put that in too.

    Time to test this machine I thought. Having no power cable was a problem, so I just looked at the back of the machine to see a standard power plug, found a matching cable somewhere about the house, hooked everything up and prayed when I hit the power switch.

    But nothing.

    Not a single sound.

    I had heard of PRAM problems with the iMac G3, so I hit the reset switch a couple of times. Still no luck. What worries me is that there is not a single sound coming from the machine.

    Could I have put the battery in wrong, or should I keep going with the reset switch? Will doing either of these things give it a kick start to life?

    Regardless, if anyone has any ideas on how to get this working, I'd be much appreciated. Could it be that my power cable isn't providing enough power? I would have thought the plug socket at the back of the iMac means that I'm most likely to compatible power cord, but I may be wrong...

    But, if as I'm hoping is not the case, this is a lost cause, what do you think is my best option? I see two options. Either selling it whole, or parting it out. Bear in mind, I don't know whats wrong with the machine, but there is the Slot loading drive, casing, logic board etc... that are all up for parting out. Since I'm saving for my Gap Year, I'm trying to raise as much possible. What way do you think will give me back most profit? Is eBay the way to go? What kind of total do you think I'll be looking for?

    Many thanks for your help.

  2. macfreek57 macrumors 6502

    Jan 1, 2002
    Baton Rouge, Louisiana
    you definitely could get some good money for the parts on ebay (I would do as many separate listings you can). but i don't think it's a completely lost cause.
    If you had any information on the machine's history especially what conditions (humidity, droppage etc) it's been under, it might help to determine the problem. essentially, if the motherboard has something wrong with it (short circuit, broken, rusted etc.), you might as well sell the parts. You can't do much to fix a motherboard. The only thing I would suggest if you think it might be the motherboard is to reset the PMU. There should be a red button somewhere on your motherboard (if it's not red ABSOLUTELY DON'T PUSH IT!! I'm just kidding, i think most of them are red, but if yours is not then no big deal; there shouldn't be too many buttons on a motherboard anyway, so I think it would be safe to say that there's only one and it's the PMU reset). While the machine is off, press it. Nothing exciting happens when you do, so if you're not sure if you did, I don't think it's a problem if you wait a minute and press it again. I just wouldn't press it too much.
    So if it's not the motherboard, then it's one of the other components or connections. Common components to check are the power supply (the metal brick INSIDE the machine), RAM (definitely make sure that you have good RAM; this is something that will cause your machine to entirely not work; don't assume that it will work just because it fits in the slot; find out what type of RAM the motherboard needs and try to match these specs exactly), processor (although I don't think your processor is removable), video card (it's probably integrated into the board which means if it's broken there's nothing you can do), hard drive (probably not an issue here since your machine is not even booting, but you will need to have a working operating system compatible with the machine's processor, memory and video card, or you will need the ability to install said operating system, i.e. access to a functioning cd/dvd drive), battery (make sure it works, but I don't think this would keep the machine from booting), and make sure you have good drive cables and that all of your connections are snug in place. As far as compatibility of power cords, I don't think you'll have to worry about that. Suffice to say that if it looks like it fits and it does, then you're good. This is because the computer has it's own power converter. It's expecting the voltage coming out of the wall and should be able to convert it into a usable voltage and whatnot (I assume you're in the UK, which I am not, so I don't really know what voltages are used there, but I think that if you bought it in the UK and you are using standard connections, everything should be fine).
    You should also be attempting to boot with a minimal amount of peripherals connected (I would even recommend trying without the mouse and keyboard plugged in; usb devices can cause problems like this, although I have never personally known them to).

    There's my two-bit, half-assed, incomplete-because-I-haven't-done-it-in-so-long-and-I'm-tired-anyway-so-leave-me-alone mac troubleshooting guide.
  3. Rocksaurus macrumors 6502a


    Sep 14, 2003
    Without it making any noise whatsoever doesn't it seems like it's probably a power supply issue or possibly a motherboard issue though in that case you'd expect the monitor or a fan or something to power on. I dunno where to get a PS for an iMac though that would seem like a logical fix... It could also be a power supply connection issue. Everything plugged in? I was thinking it'd be cool if you made a fish tank out of it if it doesn't work though, you know, like they've done w/ old classics!? But yeah, sorry I can't be of more help.
  4. sreedy macrumors 6502a

    Feb 24, 2005
    This sounds like the same problem I have with my iMac G3, tried everything and it's still dead..... got a friend with some electrical experience and G3 electric guide and discovered there wasn't quite enough amps reaching the hard drive and it couldn't spin-up..... not sure quite what to do even though I know the issue now.
  5. Borjan thread starter macrumors regular

    Sep 28, 2004
    Thanks for the help guys...

    I read up a bit about testing for the trickle voltage reaching carious parts of the components, but I don't have the tools necessary to do any testing! :(

    Any more help is much appreciated, especially from those who have seen my problem before...

    Does anyone know if the power board on the iMac is an easy replace? My gut feeling is 'no'...
  6. tomacintosh macrumors regular

    Aug 25, 2005
    I think I'm going to be in the same boat soon, my girlfriend just won an imac g3 600Mhz on ebay for £25, it has no ram, hdd, cddrive or speakers. I've got the ram, hdd and speakers ready to go in so far. Trouble is the guy sold it as dead, and he thinks its the Power/Analog/Video board that's gone. Could be what's gone on yours, it basically runs the whole system.
  7. disconap macrumors 68000


    Oct 29, 2005
    Portland, OR
    This would be my guess for the problem (also check to make sure that the motherboard has a processor, though that might be a "duh" statement). Just because the RAM stick fits doesn't mean it's the right kind; in fact, there is plenty of almost perfectly spec'ed RAM out there that just doesn't work in Macs. So I would highly suggest testing it with a borrowed PC100 RAM stick from a working machine and see if that helps.

    Otherwise, my idea for my older imac (once it dies) is to buy a small flat panel monitor and a refurbished Mac mini and make it a speedy G4...

    EDIT: No noise or power at all? Hmm, that wouldn't be the RAM, then. But if you get it sorted, I still suggest the above, at least when testing it...
  8. California macrumors 68040


    Aug 21, 2004
    There's a local guy here in LA who seems to specialize in old G3s. He may have the board or whatever part you are looking for. Always check your power cord, I heard these G3 cords sometimes went bad. If you want the email for the guy, let me know.
  9. Borjan thread starter macrumors regular

    Sep 28, 2004
    California, yeah, maybe you could PM the email of your friend to me.

    I live in London, so I wont be looking to buy any parts, but maybe a speaking to a specialist will help me out loads.

    From what people are saying, I have a sneaking suspicion that my PAV board has gone...
  10. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    I long time ago I used to fix computers, that was back when we used to de-solder parts off the boards and put in replacments. From that experiance I'd guess you simply have a power supply failure. Do you own a volt meter? If not buy one, a cheap one is good enough, and check the DC side of the power supply. One tip. You may need to check the DC voltages under load, don't check it when disconected from the computer as many times they don't "turn on" when disconnected unless you know the trick..
  11. Borjan thread starter macrumors regular

    Sep 28, 2004
    Okay after letting the iMac sit in my room for a while, I've decided to retackle this issue...

    While I haven't checked the trickle voltage, I will most likely just assume its the PAV board and try to find a spare...

    But looking on eBay, I can't really seem to find any. They seem to be quite rare. (Remember I'm in the UK folks)

    Anyone have a good place to get PAV boards from?

    If not, maybe I'll try the ATX power mod.. though I really dont have much more experience with electronics than wiring a plug!

    Still, I could learn...

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