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Can someone please help me troubleshoot this G5?

domini99

domini99

macrumors member
Original poster
Sep 1, 2014
62
7
Hi all,

A couple of days ago I got a PowerMac G5 dp 1.8 identical to the one I already had, but this one is showing strange behaviour.

When you turn it on, it makes very strange squeeky and beeping noises. Not beeping as in unsuccessful post, but beeping like a phone charger does when you don't plug your phone in it.

It posts normally and boots into OS X.
After bootup, the noises stop and only reoccur sometimes, completely random.

Now sometimes, when I start it it turns on and chimes, but shows a dark grey screen and does nothing.

Most of the time it boots normally, but it doesn't run as fast as my other identical G5.

I swapped the RAM from my disassembled G5 and put it into this one, no change.

Fans all operate about normally, but sometimes they randomly ramp up to full speed and than go back to normal again.

I've had to randomly reset NVRAM twice because it didn't want to turn on.

It doesn't exactly seem to get worse, but the machine for sure isn't running well.

Hardware I've checked:
Hard drive
RAM
Graphics Card
All fans.


But I can't find what the issue is, and neither can I find the source of the noises.
I'll record them tomorrow so you can hear them too.


Does anybody know where I should start to look?
 
When it's running normally is there anything peculiar about it?

Right away, assuming you have checked all other hardware (as you mentioned) I would suspect either a CPU (you said this was a dual) or the logicboard.
 
Yeah I checked all the hardware that is easily removable.

When the system boots and runs, it runs fairly normal, just not very quick.
It freezes up for like 10 seconds every once in a while, but it hasn't stopped working yet.

I've tried to just use it for a couple of hours, it doesn't crash or lock up, but does get random stutters and overall it doesn't run very well.

It shows both CPU's operating and recognises all installed RAM.

The same RAM functions fine in any other PC and passes memtest on my Pentium 4 rig.

Hard drive has no bad sectors or SMART errors, and the GPU works fine in my other powermac.
I've also tried just plugging my good G5 hard drive with a dual-boot of Linux and OS X 10.5 on it in my "bad" G5 and it recognises the drive and boots OS X, it can't boot Linux. (Lubuntu 14.04).

As soon as I press the L button on the yaboot prompt, the screen glitches and the Mac reboots in boot disk selection mode, but it looks severely distorted. I'll add a picture of it tomorrow.

After that happened, the Mac fails to boot OS X completely (dark grey screen) unless I reboot it a couple of times or remove the power cable.

I removed the original 1GB of RAM it came with.
 
domini99 said:
Yeah I checked all the hardware that is easily removable.

When the system boots and runs, it runs fairly normal, just not very quick.
It freezes up for like 10 seconds every once in a while, but it hasn't stopped working yet.

I've tried to just use it for a couple of hours, it doesn't crash or lock up, but does get random stutters and overall it doesn't run very well.

It shows both CPU's operating and recognises all installed RAM.

The same RAM functions fine in any other PC and passes memtest on my Pentium 4 rig.

Hard drive has no bad sectors or SMART errors, and the GPU works fine in my other powermac.
I've also tried just plugging my good G5 hard drive with a dual-boot of Linux and OS X 10.5 on it in my "bad" G5 and it recognises the drive and boots OS X, it can't boot Linux. (Lubuntu 14.04).

As soon as I press the L button on the yaboot prompt, the screen glitches and the Mac reboots in boot disk selection mode, but it looks severely distorted. I'll add a picture of it tomorrow.

After that happened, the Mac fails to boot OS X completely (dark grey screen) unless I reboot it a couple of times or remove the power cable.

I removed the original 1GB of RAM it came with.
Click to expand...
This is a common issue with the G5's. It is the PSU, try putting the processor settings to reduced and see if that helps
 
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MacCubed said:
This is a common issue with the G5's. It is the PSU, try putting the processor settings to reduced and see if that helps
Click to expand...
I'll try tomorrow, thanks.
I'm going to sleep for now.
Thanks for the quick help!
 
MacCubed said:
Most of them are at this point. Reduced settings really does not impact the average user
Click to expand...
Interesting. The G5 at work still has all original (except for the logicboard, CPU and hard drive) February 2005 equipment. No issues. And that PSU has been on full power 24/7 the entire time.
 
MacCubed said:
No problem! Another thing I recommend is installing CHUD tools and enabling CPU Nap
Click to expand...
Will do,

eyoungren said:
What about a new PSU?

Or are they all bad?
Click to expand...
My other PowerMac G5 is perfectly fine. In fact, it is almost brand new.
I've reassembled that one, if I can't get this PowerMac fixed I'll use this one for my casemod and leave the good powermac to be a powermac.


eyoungren said:
Interesting. The G5 at work still has all original (except for the logicboard, CPU and hard drive) February 2005 equipment. No issues. And that PSU has been on full power 24/7 the entire time.
Click to expand...
I don't know what this thing has been doing before I got it, my good powermac has been sitting in a warehouse for over 10 years, and was still boxed.


I've recorded the sound it makes, and I found that my good powermac came with an Apple Hardware Test DVD
So i'm now running that one on the bad powermac.


I'll attach a link to the video once everything is done uploading.
 
domini99 said:
Will do,


My other PowerMac G5 is perfectly fine. In fact, it is almost brand new.
I've reassembled that one, if I can't get this PowerMac fixed I'll use this one for my casemod and leave the good powermac to be a powermac.



I don't know what this thing has been doing before I got it, my good powermac has been sitting in a warehouse for over 10 years, and was still boxed.


I've recorded the sound it makes, and I found that my good powermac came with an Apple Hardware Test DVD
So i'm now running that one on the bad powermac.


I'll attach a link to the video once everything is done uploading.
Click to expand...
My 2.0GHz Dual Processor from 2004 has the same issue, and what I suggested above worked for me. Apple did have a recall program on the PSUs for squeaking. Mine was annoying to a point, but I ended up getting used to it, as download speeds are slowed on reduced mode
 
MacCubed said:
My 2.0GHz Dual Processor from 2004 has the same issue, and what I suggested above worked for me. Apple did have a recall program on the PSUs for squeaking. Mine was annoying to a point, but I ended up getting used to it, as download speeds are slowed on reduced mode
Click to expand...

After the hardware test is done I'll set it to reduced and see it it fixes the stability issues.
In the meanwhile, I've found a video on YouTube of a PowerMac that also has ramping fans,
this video shows exactly what my G5 does from time to time:

Just goes up, and down again.

I've made a video covering the whole thing, with MLG Video editing (took me 10 minutes to make this entire thing, I'm not lazy, I'm just on power saving mode)
I'm sorry, my voice is terrible at the moment, I've caught a pretty bad cold.
Also, you'll hear a fan rattling. It's my sound recorder's cable hitting the PCI area fan, it didn't fit anywhere otherwise.
In this video you can clearly hear the popping and screeching noises it makes,
 
domini99 said:
After the hardware test is done I'll set it to reduced and see it it fixes the stability issues.
In the meanwhile, I've found a video on YouTube of a PowerMac that also has ramping fans,
this video shows exactly what my G5 does from time to time:

Just goes up, and down again.

I've made a video covering the whole thing, with MLG Video editing (took me 10 minutes to make this entire thing, I'm not lazy, I'm just on power saving mode)
I'm sorry, my voice is terrible at the moment, I've caught a pretty bad cold.
Also, you'll hear a fan rattling. It's my sound recorder's cable hitting the PCI area fan, it didn't fit anywhere otherwise.
In this video you can clearly hear the popping and screeching noises it makes,
Click to expand...
The up and down fan speeds is caused by the G5 being set to "Automatic" in the energy panel. In reduced mode, the fans are always low, in highest mode fans are set to max, and in the automatic mode, they fluctuate
 
MacCubed said:
The up and down fan speeds is caused by the G5 being set to "Automatic" in the energy panel. In reduced mode, the fans are always low, in highest mode fans are set to max, and in the automatic mode, they fluctuate
Click to expand...
Okay cool.
It's been 2 hours and the hardware test still hasn't finished yet, I guess we'll be waiting...
 
So the test completed without any errors, and I've set performance to reduced, the system doesn't seem to run significantly better, but I was making my homework and I had some PDF Files open on the machine, and I noticed something.

It was like zip.... zip.... zip.... zip..... every second, and it was comming from the bottom of the tower, so I indeed think the PSU is to blame. So far it is perfectly usable, but it just tends to hang up for a couple of seconds once every while.
I've put my good G5 together again to compare, and the bad G5 runs just a tad slower than my good G5.

Here, listen:

What do you think?
 
domini99 said:
So the test completed without any errors, and I've set performance to reduced, the system doesn't seem to run significantly better, but I was making my homework and I had some PDF Files open on the machine, and I noticed something.

It was like zip.... zip.... zip.... zip..... every second, and it was comming from the bottom of the tower, so I indeed think the PSU is to blame. So far it is perfectly usable, but it just tends to hang up for a couple of seconds once every while.
I've put my good G5 together again to compare, and the bad G5 runs just a tad slower than my good G5.

Here, listen:

What do you think?
Click to expand...
I definitely think it's the PSU, did you try CHUD tools yet?
 
MacCubed said:
I definitely think it's the PSU, did you try CHUD tools yet?
Click to expand...
I've tried them and played around with it a little and it seems to do something, but the sound is getting worse by the hour.
This morning you couldn't hear it while idling.
This afternoon the zipping sound became noticeable, and now it's screaming noticeably during idle.

The machine keeps working fine, and I've been using it instead of my main PC purely for testing, but I feel like it isn't going to live very long anymore.

Now about it, even during the few minutes I was typing this message it became worse.
 
Little update:
I've completely taken apart the bad PowerMac G5 and ran it outside of the case, and to my surprise..
The PSU is not the noise producer at all!
The sound comes from the motherboard itself, somewhere around where the CPU's are located.
That's strange, I've never heard a motherboard make sounds like this. I've heard PSU's do all kinds of things, but this is strange.

I've even connected the PSU of my good G5, and the screeching/whining noise is still there.
 
Check out this video www.youtube.com/watch?v=4521HSi0r4E

The creator claims the issue is defective solder (solder fault) on the mother board - his solution is to 're-solder' the board by baking it.

At 11 minutes he disassembles an air cooled dual processor G5
At 15 minutes he begins the baking section

I'm not a fan of the "oven trick", it just seems very risky. If I was at the 're-solder' stage a "heat gun" would be my tool of choice.

If you do disassemble your G5 check the U3 System Controller / Bus Bridge IC heatsink assembly. There is a good write up on repairing it here www.thinkclassic.org/viewtopic.php?id=106

Finally let me say that if you decided to do this - mark each CPU so it can be reinstalled at the same location.

Good luck and keep us posted of your findings / progress.
 
Welp
-
Left it unplugged overnight,
Came back to it today, won't turn on anymore at all.

No I signs of power, it's like if the cable would be unplugged.
 
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