PowerMac G5 Booting Issue

jeremylanders · Mar 9, 2013

I have a Power Mac G5 here are the specs:
Hardware Overview:

Model Name: Power Mac G5
Model Identifier: PowerMac11,2
Processor Name: PowerPC G5 (1.0)
Processor Speed: 2 GHz
Number Of CPUs: 2
L2 Cache (per CPU): 1 MB
Memory: 2.5 GB
Bus Speed: 1 GHz
Boot ROM Version: 5.2.7f1

I am having a problem where the machine will boot up only after it has been unplugged for about 20-30 minutes. Once I boot it up, it is able to be restarted with no problems. And when I say restarted I mean executing a restart for the menu. The problem is when the machine is shut down completely it will not reboot until it has been unplugged for 20-30 minutes. Can someone please tell me what the problem may be and how to resolve the issue? Thank you for your time.

Intell · Mar 9, 2013

Those types of problems are usually caused by a bad capacitor in the power supply.

jeremylanders · Mar 9, 2013

I just dont understand why it will boot up without issue after it has been unplugged for 30 minutes. It will reboot just fine. It seems to be working just fine in every other capacity. It's just baffling to me.

Intell · Mar 9, 2013

A failing capacitor wont' work when it's freshly plugged in sometimes. But after it's been plugged in, the capacitor starts to charge and work again. That's why it can restart without a problem, the capacitor still has a charge in it. Before long, that capacitor will fail completely and it won't work at all.

jeremylanders · Mar 9, 2013

But the thing is it will work after its been freshly plugged in. See I have to unplug it for 30 minutes at least then plug it back in and it will boot right up.

Why can't I just keep it plugged in all the time and be able to start it up. If its continuously plugged in after a shut down it will not start back up.

bc2000 · Mar 5, 2014

Mac G5 Issue

Hi Jeremy, Did you ever find a fix for your issue? Mine is doing the same thing. Thanks.

AmestrisXServe · Mar 5, 2014

That is a rather odd problem: Does the power light engage, and do any components power up, before the system halts, or does it do nothing at all when you press the power button?

Does the white lamp on the power button flash briefly, once, or more times? (If so, please describe the pattern of flashes.)

As with anything else, ZAP the PRAM first. Unplugging the G5 should reset the PMU, after 30 seconds; not 30-minutes.

Write what happens when you do a PRAM Zap, without unplugging the system for a long time; and if it restarts properly without going through this.

What causes you to have a need to reset the system? Does it crash, or exhibit any odd behaviour, necessitating the restart?

Stephen Dowling · Apr 2, 2014

I'm not trying to hijack this thread, but I'm having a similar issue with the same model G5 as the OP. Like the OP, my G5 sometimes has to be unplugged for a little while, and then plugged back in to boot correctly. Although, that hasn't been working lately.

My G5 will power on, chime, no red error LEDs lit, power LED remains solid...but it always gets stuck on the apple logo and the fans rev up to full speed within a couple of minutes. PRAM reset wont chime. Also, I've observed that the G5 will not boot from either internal HD slots, won't boot from tiger install disk (it would previously), and it won't let me force it to boot from USB in Open Firmware (which it previously did.) It will, however, boot from my Apple Hardware Test DVD. I've run the full diagnostic test multiple times, and each time everything passes!

On a side note, memory is in matched pairs and works fine in a different G5 of the same exact specs. Both internal HDs and Tiger install DVD work fine on my other G5s as well.

Anyone have any suggestions? I'm hoping any info on this issue will help out the OP as well!

Altemose · Apr 6, 2014

Stephen Dowling said:
I'm not trying to hijack this thread, but I'm having a similar issue with the same model G5 as the OP. Like the OP, my G5 sometimes has to be unplugged for a little while, and then plugged back in to boot correctly. Although, that hasn't been working lately.

My G5 will power on, chime, no red error LEDs lit, power LED remains solid...but it always gets stuck on the apple logo and the fans rev up to full speed within a couple of minutes. PRAM reset wont chime. Also, I've observed that the G5 will not boot from either internal HD slots, won't boot from tiger install disk (it would previously), and it won't let me force it to boot from USB in Open Firmware (which it previously did.) It will, however, boot from my Apple Hardware Test DVD. I've run the full diagnostic test multiple times, and each time everything passes!

On a side note, memory is in matched pairs and works fine in a different G5 of the same exact specs. Both internal HDs and Tiger install DVD work fine on my other G5s as well.

Anyone have any suggestions? I'm hoping any info on this issue will help out the OP as well!

The fans ramping up because it couldn't complete startup is completely normal. The G5's fan system is totally computerized and requires a driver to be loaded to control it. Don't worry about that aspect.

I would try replacing the PRAM battery. It may seem like a long shot, but definitely worth a try. If you do not want to buy one, try borrowing one from your other G5 you mentioned. I have had G5s not start because of them.

Stephen Dowling · Apr 7, 2014

Altemose said:
The fans ramping up because it couldn't complete startup is completely normal. The G5's fan system is totally computerized and requires a driver to be loaded to control it. Don't worry about that aspect.

I would try replacing the PRAM battery. It may seem like a long shot, but definitely worth a try. If you do not want to buy one, try borrowing one from your other G5 you mentioned. I have had G5s not start because of them.

I should have mentioned that at the time of posting, I had a new PRAM battery on the way! I would've used the battery from the other G5, but the models are different and use different batteries.

Anyways, I got the new PRAM battery in the mail a couple days ago; I replaced the battery and booted into Open Firmware to reset NVRAM and OF itself to be on the safe side. After that, it booted into Tiger like it was supposed to and ran for 30 minutes or so before it kernel panicked.

After that, I shut down, unplugged for a couple minutes, and it booted back up normally and ran for several hours until I shut it down for the night.

Thinking all was well, I booted it up the next morning to upgrade it to Leopard...back to the same old getting stuck on the Apple logo. It only gets stuck when trying to boot from any internal HD or and OS X install DVDs (10.3, 10.4,10.5); however, it will boot from my ASD 2.5.8 disk every single time. I ran the hardware diagnostics and everything passed, of course.

After that, I booted in verbose mode (command+v) to see where it was hanging. It would always hang early on in the process after saying "DART enabled".

On a side note, any time I try to reset NVRAM and OF from within Open Firmware; NVRAM will reset (at least it says it does), but anytime I try to reset Open Firmware (reset-all), it hangs after I push enter and the fans eventually ramp up and I'm forced to shut down.

This one has definitely got me stumped! Thanks for your reply; I appreciate it!

Altemose · Apr 7, 2014

Stephen Dowling said:
I should have mentioned that at the time of posting, I had a new PRAM battery on the way! I would've used the battery from the other G5, but the models are different and use different batteries.

Anyways, I got the new PRAM battery in the mail a couple days ago; I replaced the battery and booted into Open Firmware to reset NVRAM and OF itself to be on the safe side. After that, it booted into Tiger like it was supposed to and ran for 30 minutes or so before it kernel panicked.

After that, I shut down, unplugged for a couple minutes, and it booted back up normally and ran for several hours until I shut it down for the night.

Thinking all was well, I booted it up the next morning to upgrade it to Leopard...back to the same old getting stuck on the Apple logo. It only gets stuck when trying to boot from any internal HD or and OS X install DVDs (10.3, 10.4,10.5); however, it will boot from my ASD 2.5.8 disk every single time. I ran the hardware diagnostics and everything passed, of course.

After that, I booted in verbose mode (command+v) to see where it was hanging. It would always hang early on in the process after saying "DART enabled".

On a side note, any time I try to reset NVRAM and OF from within Open Firmware; NVRAM will reset (at least it says it does), but anytime I try to reset Open Firmware (reset-all), it hangs after I push enter and the fans eventually ramp up and I'm forced to shut down.

This one has definitely got me stumped! Thanks for your reply; I appreciate it!

I am thinking to try swapping the video card with another G5. Some Nvidia cards have caused that on some old Macs that I have seen.

Maybe Intell has some experience in this area?

Intell · Apr 7, 2014

A video card switch may fix it. Not overly sure in this case.

Altemose · Apr 7, 2014

Intell said:
A video card switch may fix it. Not overly sure in this case.

The only reason I brought it up is that times when I had this issue, it was always with Nvidia cards.

Stephen Dowling · Apr 8, 2014

Altemose said:
I am thinking to try swapping the video card with another G5. Some Nvidia cards have caused that on some old Macs that I have seen.

Maybe Intell has some experience in this area?

I appreciate your advice! I remember seeing something about a faulty GPU causing these symptoms; I wish I could switch one of the GeForce 6600LE cards from one of my DC G5s, but they're all PCIe cards and this G5 is AGP

...this may be a silly question, but I haven't finished my coffee yet this morning and I don't feel like digging around for my B&W G3 to check

But, would I be able to temporarily use the graphics card from my G3 (ATi Rage 128, I believe) in place of the FX 5200 that is currently in my G5; just to see if the FX 5200 is causing the no-boot problem? Are they even the same slot type?

Also, I've read where some people with similar issues have been able to fix their machines by re-seating the CPUs? I'll probably end up re-seating them anyways, just for the sake of knowing they're snug. I should also note, I've tried disabling one of the CPUs in Open Firmware to see if it would boot--that way I could at least narrow it down to being CPU related. Didn't make a difference, of course!

Thanks for all of the suggestions; I really appreciate everyone's help!

Altemose · Apr 8, 2014

Stephen Dowling said:
I appreciate your advice! I remember seeing something about a faulty GPU causing these symptoms; I wish I could switch one of the GeForce 6600LE cards from one of my DC G5s, but they're all PCIe cards and this G5 is AGP

...this may be a silly question, but I haven't finished my coffee yet this morning and I don't feel like digging around for my B&W G3 to check But, would I be able to temporarily use the graphics card from my G3 (ATi Rage 128, I believe) in place of the FX 5200 that is currently in my G5; just to see if the FX 5200 is causing the no-boot problem? Are they even the same slot type?

Also, I've read where some people with similar issues have been able to fix their machines by re-seating the CPUs? I'll probably end up re-seating them anyways, just for the sake of knowing they're snug. I should also note, I've tried disabling one of the CPUs in Open Firmware to see if it would boot--that way I could at least narrow it down to being CPU related. Didn't make a difference, of course!

Thanks for all of the suggestions; I really appreciate everyone's help!

I think that it is a different type of AGP in the G5. If it is a PCI card you can give it a shot, just remember to disconnect the Nvidia card first.

If you reseat the CPUs, make sure you put fresh thermal paste on and recalibrate them in ASD 2.5.8.

Stephen Dowling · Apr 8, 2014

Altemose said:
I think that it is a different type of AGP in the G5. If it is a PCI card you can give it a shot, just remember to disconnect the Nvidia card first.

If you reseat the CPUs, make sure you put fresh thermal paste on and recalibrate them in ASD 2.5.8.

Will do. I've got a fairly new tube of Arctic Silver and ASD 2.5.8 is already in the drive

I'll post back here with whatever results I get!

Thanks!

Altemose · Apr 8, 2014

Stephen Dowling said:
Will do. I've got a fairly new tube of Arctic Silver and ASD 2.5.8 is already in the drive

I'll post back here with whatever results I get!

Thanks!

No problem. Make sure you get the old paste off first. I recommend using a rubber latex glove and smearing the paste over to ensure it is covered.

Stephen Dowling · Apr 17, 2014

Hey everyone,

I re-seated the CPUs and re-applied the thermal paste. Its still doing the same thing as before.

However, I have made some "progress" if that's what you want to call it. Every once in a while, I can get it to boot by doing the following: Unplug the computer for a few minutes, plug it back in, press and hold the power button through the first chime and release it as soon as it chimes again and takes me into Open Firmware, type reset-nvram and hit enter, type set-defaults and hit enter, type reset-all and then hit enter; if it doesn't hang after reset-all then it will boot. However, once booted it will usually freeze within 20 minutes regardless of whether its sitting at idle or being used.

The above method only works 4/10 times, needless to say I'm still stumped.

Altemose · Apr 17, 2014

Stephen Dowling said:
Hey everyone,

I re-seated the CPUs and re-applied the thermal paste. Its still doing the same thing as before.

However, I have made some "progress" if that's what you want to call it. Every once in a while, I can get it to boot by doing the following: Unplug the computer for a few minutes, plug it back in, press and hold the power button through the first chime and release it as soon as it chimes again and takes me into Open Firmware, type reset-nvram and hit enter, type set-defaults and hit enter, type reset-all and then hit enter; if it doesn't hang after reset-all then it will boot. However, once booted it will usually freeze within 20 minutes regardless of whether its sitting at idle or being used.

The above method only works 4/10 times, needless to say I'm still stumped.

Sounds like bad RAM or a power issue.

Stephen Dowling · Apr 17, 2014

Altemose said:
Sounds like bad RAM or a power issue.

I've tested it with multiple sets of compatible RAM that is known to be working; I should've mentioned that earlier!

I'm starting to think maybe its a power issue as well, any ideas on how to go about testing the power supply??

Altemose · Apr 17, 2014

Stephen Dowling said:
I've tested it with multiple sets of compatible RAM that is known to be working; I should've mentioned that earlier!

I'm starting to think maybe its a power issue as well, any ideas on how to go about testing the power supply??

Well, Intell specializes in this area. Normally I connect a voltmeter, but this sounds like a failing capacitor as Intell said earlier in the thread.

Depending on how the Logic Board's caps look, you may want to pull the PSU. With the PSU open you can inspect for any bulging or leaking caps. They are the battery looking things on the board.

If you see anything out of whack you are left with three options. Rebuild the PSU with all new caps, replace the damaged or affected capacitors, or order a new PSU that is affordable.

Once again, this is Intell's type of game. I mainly deal with networking hardware.

Stephen Dowling · Apr 18, 2014

Altemose said:
Well, Intell specializes in this area. Normally I connect a voltmeter, but this sounds like a failing capacitor as Intell said earlier in the thread.

Depending on how the Logic Board's caps look, you may want to pull the PSU. With the PSU open you can inspect for any bulging or leaking caps. They are the battery looking things on the board.

If you see anything out of whack you are left with three options. Rebuild the PSU with all new caps, replace the damaged or affected capacitors, or order a new PSU that is affordable.

Once again, this is Intell's type of game. I mainly deal with networking hardware.

If I have time today I'll pull the PSU and assess the situation. I've got to finish refurbishing a MacBook Pro 1,1 for a client, and then I've got to replace the exhaust manifold on my grandfather's car. Busy, busy, busy!

If not today, I'll pull the PSU tomorrow and post back with my findings.

I really appreciate all of your help!

Altemose · Apr 18, 2014

Stephen Dowling said:
If I have time today I'll pull the PSU and assess the situation. I've got to finish refurbishing a MacBook Pro 1,1 for a client, and then I've got to replace the exhaust manifold on my grandfather's car. Busy, busy, busy!

If not today, I'll pull the PSU tomorrow and post back with my findings.

I really appreciate all of your help!

Have fun doing the manifold. Really fun depending on the engine of course.

Rebuilding a PSU isn't terribly hard if you are competent with a soldering iron.

TJHappy · Apr 29, 2014

Hi G5ers. I'm a nubie to this site. I have two G5 Dual 1.8 towers. They are a mastery of design!
However, I do have some issues with both.

I bought them both on eBay about 5 years ago at around $450 each - shipped.
I got them to upgrade myself from my G4 466DA, AND to get my elderly mother off of the confusing Windows running PCs my brothers kept setting her up with ( and then not supporting!). She went through three PCs in 7 years!
I wanted our computers to be set up identical so I could help her over the phone if she had problems (I was tired of having to do that for the PCs).

After I got the G5s I never actually had to help her agian for several years!.....until lately.

They both came from different sellers and were loaded with software and RAM (4.5 GB on mine and 2.5 on her's - i think)

I moved about a year ago, and when I went to boot up at the new place my G5 would not boot. It gave me the chimes but past that would only spin in gray screen as the HD clicked away. I put it aside and used the G4.
The G5 has two HDs ,a 160 GB with OS 10.5.2 as boot, the other a 250GB.

Recently, I put a new 1 Tera HD in it along siide the 160GB HD and booted from CD with new OS 10.5.8 retail disc. I can now read, write to and copy from the 160GB HD! So, what was happening to the 160GB HD?

On mom's G5, it suddenly quit booting. The system will not boot even from the CD. I get good chimes and some response for about 1 minute then it freezes. Any clues?

thanks

~TJ

Altemose · Apr 30, 2014

TJHappy said:
Hi G5ers. I'm a nubie to this site. I have two G5 Dual 1.8 towers. They are a mastery of design!
However, I do have some issues with both.

I bought them both on eBay about 5 years ago at around $450 each - shipped.
I got them to upgrade myself from my G4 466DA, AND to get my elderly mother off of the confusing Windows running PCs my brothers kept setting her up with ( and then not supporting!). She went through three PCs in 7 years!
I wanted our computers to be set up identical so I could help her over the phone if she had problems (I was tired of having to do that for the PCs).

After I got the G5s I never actually had to help her agian for several years!.....until lately.

They both came from different sellers and were loaded with software and RAM (4.5 GB on mine and 2.5 on her's - i think)

I moved about a year ago, and when I went to boot up at the new place my G5 would not boot. It gave me the chimes but past that would only spin in gray screen as the HD clicked away. I put it aside and used the G4.
The G5 has two HDs ,a 160 GB with OS 10.5.2 as boot, the other a 250GB.

Recently, I put a new 1 Tera HD in it along siide the 160GB HD and booted from CD with new OS 10.5.8 retail disc. I can now read, write to and copy from the 160GB HD! So, what was happening to the 160GB HD?

On mom's G5, it suddenly quit booting. The system will not boot even from the CD. I get good chimes and some response for about 1 minute then it freezes. Any clues?

thanks

~TJ

Try a PMU reset by following the instructions here.

Also, try a new PRAM battery.

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