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PowerMac G4 Problems...

N

nater.

macrumors member
Original poster
Jul 11, 2006
92
0
I recently got my hands on a PowerMac G4 DA 733 mhz. It's been running fine for a few weeks now but just recently, it seems the power supply is failing. When you hit the power button, it lights up for a second and that's it. Am I right there? This case is kinda junky at the bottom, so only one drive fits in it.

I have a spare Quicksilver case with motherboard and power supply in it. Not sure either of those are in working conidition but is it possible to maybe just switch everything into that case and use that power supply?

If that works, then I can plug in another drive or two...

Thanks alot
 
You think so?
I tried to restart with just a 256 stick in there...

It doesn't make any noise or anything, it just flashes the light real quick.

I'll try different combo's of ram to see if I will work or something. Thanks for the response.
 
nater. said:
You think so?
I tried to restart with just a 256 stick in there...

It doesn't make any noise or anything, it just flashes the light real quick.

I'll try different combo's of ram to see if I will work or something. Thanks for the response.
Click to expand...

Those old powercords also fail. Radio Shack.
 
does the power light stay on for as long as you hold it but go off a second after you release it? i had a similar experience with a quicksilver, i had to reset the PMU/CUDA, which involved pressing a little button on the motherboard next to the battery. Turned out the problem with that computer was a nearly dead HDD, but i was very confused by the power indicator that turned on...but only for a second.

Try to locate that little reset button first, see if that's the problem.
 
Yeah, that's exactly what it is doing. As long as I hold it the light is on...but whenever i take my finger off it, it turns the light off.

I will try that when I get home from work. I had read somewhere about trying to reset the PMU. I was going to try it but I thought I heard something like you can fry your computer if you hit it too many times...or something.

Thanks again for all the replies.

I had tried another power cord - but I didn't test it first lol, I will try a few more...see what works.
 
nater. said:
Yeah, that's exactly what it is doing. As long as I hold it the light is on...but whenever i take my finger off it, it turns the light off.

I will try that when I get home from work. I had read somewhere about trying to reset the PMU. I was going to try it but I thought I heard something like you can fry your computer if you hit it too many times...or something.

Thanks again for all the replies.

I had tried another power cord - but I didn't test it first lol, I will try a few more...see what works.
Click to expand...

Is it true that resetting the PMU can hurt your Mac?
 
CanadaRAM said:
No.
But resetting it drains the PRAM battery some, so if you do it repeatedly you coulsd end up with a flat battery.

Nater, while you are working in there, put in a fresh battery, its a good $10 investment
Click to expand...

Can I pick those up anywhere - pretty much? I mean, I dont need to order it online or something?
 
You can get a replacement battery from radioshack.

I had a similar issue after I upgraded the viedocard in my Digital Audio ... mine would boot fine with the side panel open, but do exactly as yours with the panel closed. Hitting the CUDA switch fixed it.
 
Got outta work late, didn't have time to head to Radio Shack or anything. But I tried a few things anyways.

I took out the ram and tried a few different sticks - just to see if that could do anything. With zero results..darn.

I found the PRAM button, hit that - tired to turn it on...nothing.

I've tried different powercords that I know work, nothing...

Anyone else got any ideas?

I think maybe something is messed up with the hard drive. That is totally possible. I found a drive that would work outta a pc. What's the easiest way to format it to be able to work in that PM DA?
 
nater. said:
I think maybe something is messed up with the hard drive. That is totally possible. I found a drive that would work outta a pc. What's the easiest way to format it to be able to work in that PM DA?
Click to expand...

Boot from an OSX CD (hold mouse button down through the boot process to force the drive door to open, insert the CD, restart and hold the "C" key down throughout boot) If it won't boot from the CD after you put in the new battery then you have other hardware issues.

Leave in one known-good stick of RAM if you can.
 
Alrgiht...so I put in another battery...

Not working. What could it be now? Any ideas?

I think something is messed up with the HD - Can I put a drive that isn't formated to OS X?

Ugh..
 
friend of mine had a similar problem with his DA G4, turned out it was the vid card. If you have a spare, its worth a shot to switch them and see what happens

In my case, i just so happened to be replacing my Rage128 with a Radeon 9000, so i lent him my 128. Worked like a charm.

Hope this helps...
 
nater. said:
Alrgiht...so I put in another battery...

Not working. What could it be now? Any ideas?

I think something is messed up with the HD - Can I put a drive that isn't formated to OS X?

Ugh..
Click to expand...

Firstly, I don't think a bad hard drive would cause that symptom. But regardless, even if it did, booting from an OS X install CD would bypass the hard drive and allow it to boot up. Second, yes you can put whatever drive you want in it. If it is not formatted for Mac then you need to have a bootable CD or DVD of OS X in the CD/DVD drive when booting in order to run Disk Utility in order to format the drive.

If the machine won't boot from a CD/DVD, then your hard drive most certainly is not your issue. While it could be a power supply problem, generally the computer would not light up at all if it was bad.

No, you can't directly swap in a Quicksilver power supply without some modifications (but it certainly can be done fairly easily). Or, you could even go get an ATX power supply and put it in there (follow my directions in this post: https://forums.macrumors.com/threads/261623/)

I would try this: unplug the computer for a while (30 minutes), remove the battery, unplug all the PCI cards, take out the ram, unplug the IDE cables and the power supply main connector on the motherboard. Clean the motherboard with compressed air. Wipe all the metal contacts on the PCI cards and ram with a qtip and rubbing alcohol (be careful to avoid getting it on the cards' or ram sticks' circuit boards and don't have the qtip dripping wet)

Reassemble everything carefully. Leave out all but the video card and ram for now (and of course the battery, IDE and power supply connectors). Hook up whatever cables you need to the back of the computer including the power cord. Now, press and hold the motherboard reset button for five seconds. Now, press and hold the power button on the front of the Mac. Does it stay lit? Does it attempt to boot?

If not, see if you can find another video card to swap as SuperCompu2 has suggested. If so, shut it down and put everything else back and try again. Does it still boot? Then consider resetting the open firmware to default settings:

Boot holding Command-Option-O-F. At the prompt type:

reset-nvram [hit return]
set-defaults [hit return]
reset-all [hit return--at which time it will reboot]

Let us know how it goes and we'll see from there.
 
I don't think I have a spare video card anywhere that would work in a mac. I have a few other pc's - not sure if they might have one that works in it.

but, I tried what you suggested Spinne1. Nothing different has happened. WHen I push the power button, the light is on. When I let go of it, it turns off.

I guess I need to try that video card idea...

Any other ideas?
 
good luck

I have the same problem.pulled pci cards and video card no luck.pulled memory no luck,reset board,checked battery with meter conectors with meter all seems fine.tried starting from osx install cd noluck.then I noticed that the power supply fan was not working.when i push power buton internal fan comes on but not fan on power supply.
I don't know if this is my problem seems like a good place to start,also I read on a site somewhere that apple had a problem with some quantim fireball hds.
will keep digging and reading this post for help and suggestion.
 
up and running arrggg

It turns out it was the power supply.put it in ,had to reset board,then it booted.was jamming away with itunes video then it just shut off.got kernnel panic wouldn't boot up.turns out processor is bad.
guess when power supply fan went out it over heated the cpu.hope this isn't your problem to.had spare when i upgraded last year.hope i can get this replaced dual 1.6 very nice.seems like slow motion now.
nater hope you don't have all these problems good luck
 
I havent had time to fix it or even look at it. I'm going to try to find a video card and switch that - hopefully that does something.

Before the problems happened, the computer was shut down at night - then in the morning it wouldn't turn back on...

Like I said before - I have that spare G4 Quicksilver case. The only thing in it is the motherboard and powersuppy. Not sure if either work - but is it possible to just like switch everything over? haha or is that too easy? Even if there is some work to do to get it to work - that would be awesome to know what I would need to do.

Thanks again everyone for the replies.
 
Wait a sec...

That's MDD suppy to fit into a DA or QS.

...and the 2 power supplies I have look the same...the DA and the QS.

hmm...
 
Sorry to bring this old thread back - but finally got my hands on a Video card for my old DA that isnt working.

I have a Quicksilver Powersupply sitting around doing nothing - how hard would it be to put that in place of the old one in the DA? I think the problem is the Powersupply. I have tried everything else.

Where can I find some instructions on how to do this? Or if anyone has a DA suppy for sale - I wouldnt mind buying it.

Or Could I just swap everything into the Quicksilver? Processor and such?

Thanks for all the help
 
I've got a new mac. It works great. Thanks...but I can't just throw away a mac!

Plus, it's interesting to me to learn more about these - so Im trying to get it working and asking for advice.

Anyone else mind helping me?
 
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