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StUPoT

macrumors member
Original poster
May 23, 2011
70
0
Hi I recently acquired G5 for free from a listing on gumtree cos of a house clearance and thought 'hey it's old but why not'.

Anyways, I got it home and turned it on and the flashing folder appeared. So fair enough i put my Leopard disc in the drive and it fires up into the install menu. No probs there...

As it starts to install however, its freezes... No mouse activity or keyboard.. nothing! Then the fans start their impression of a jet engine!

After a few more goes and the same thing happening I thought I would investigate inside. Nothing wrong there either. No water spill as this one luckily isn't water cooled and everything looked fine.

So I jumped on the web and found some things to do like the lil button on the logic board and heating ram slots with a hairdryer and removing the bottom CPU etc etc but it still does the same, and sometimes it chooses not to boot aswell.

I checked the power supply and no probs either.

So Im guess what im asking is... The LogicBoard nackered? As I have no more ideas of things to do

Thanks for any help
 

Zotaccian

macrumors 6502a
Apr 25, 2012
645
7
First of all perform PRAM and SMC resets, just in case and then try installation.

It however sounds like motherboard failure. Very common on PowerMac G5's. The problem is usually the chipset/memory controller being disconnected because of a solder failure which occurs after repeated heating and cooling cycles. I think this is the case here. The chipset on these machines run insanely hot during use, if I recall right temperatures were like 70-80 celcius, never seen this kind of temperatures with any PC that I have owned, maybe half of even less of those temps.

What you can also try is to test with known good memory to rule it out, if you have original install disks they have Apple Hardware Test which can be used, but the thing is that in this motherboard failure case it might say that no problems even though there clearly is when operating system cannot be installed or booted.

If it is the motherboard failure, the fix would be to either replace the motherboard or perform reflow/reball of chipset.
 
Last edited:

StUPoT

macrumors member
Original poster
May 23, 2011
70
0
Is the memory controller on the underside of the logic board under a heatsink?
Do you think cooking it in an oven would sort it? I have done this with a few MacBook Pros and they have always worked afterwards.
I havn't got anything to loose really as it appears the board is bust anyway.
 

im_the_guy

macrumors newbie
Dec 15, 2017
8
0
I had the same issue when i got my PowerMac G5 2.0Ghz from eBay. I tried wiping the hard drive (the previous owner didn't). So anyway
im now at the stage of installing the Mac OS X disk into the computer and shortly after clicking install software, my machine also turns into an Airbus A380, turning the fans up to maximum speed.
I resolved this issue by doing this operation a few times, and if the computer did go into complete meltdown, i would hold down the power button on the front for a few seconds and force kill the machine. Before you try and wipe the HDD though, i recommend making a backup of the software, just incase the computer doesn't like the disks.

im_the_guy
 

AphoticD

macrumors 68020
Feb 17, 2017
2,283
3,462
@im_the_guy Can you try downloading, burning and running ASD?

If I recall correctly, ASD v2.5.8 was for G5s prior to the late 2005 model and then v2.6.3 was for that last rev.

I have a first gen G5 (dual 1.8ghz) which has been a bit flaky with random intermittent crashes occurring every few weeks. ASD determined one of the RAM chips on the outer set had failed testing, so I tried other DIMMs I had and it continued to fail. I ultimately just removed RAM from these slots and it passed testing with flying colors and has been solid since.
 

im_the_guy

macrumors newbie
Dec 15, 2017
8
0
I did do a check of my machine (by holding down the 'd' key right after clicking the on button) and my machine was fine, all ram working and motherboard fine.
 

AphoticD

macrumors 68020
Feb 17, 2017
2,283
3,462
I did do a check of my machine (by holding down the 'd' key right after clicking the on button) and my machine was fine, all ram working and motherboard fine.


I didn’t realize the G5 had a built in diagnostics mode. I haven’t heard of this before. It would be worth trying the Apple Service Diagnostics (ASD) as it is possibly the most comprehensive test.
 

pl1984

Suspended
Oct 31, 2017
2,230
2,645
I had the same issue when i got my PowerMac G5 2.0Ghz from eBay. I tried wiping the hard drive (the previous owner didn't). So anyway
im now at the stage of installing the Mac OS X disk into the computer and shortly after clicking install software, my machine also turns into an Airbus A380, turning the fans up to maximum speed.
I resolved this issue by doing this operation a few times, and if the computer did go into complete meltdown, i would hold down the power button on the front for a few seconds and force kill the machine. Before you try and wipe the HDD though, i recommend making a backup of the software, just incase the computer doesn't like the disks.

im_the_guy
Are you aware this thread is five years old?
 
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im_the_guy

macrumors newbie
Dec 15, 2017
8
0
I didn't run an ASD on my PM G5. By holding down the 'd' key right after turning on the computer, you launch your machine into basically a recovery mode. From there, you can run an AHT (Apple Hardware Test) which was the one I ran.
 
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