G5 Constantly Crashing

[daveyanthony]

I have a PowerMac G5 Dual 2.0GHz (June 2004) and everything has been going fine until recently. My Leopard install had gotten corrupted somehow so I tried to reinstall from USB which was going fine until halfway through the install when it is copying files, the installation crashes. I also tried this with a Tiger retail disk and it crashes as well. I decided to try my restore discs that came with it, which are 10.3.5 and that also crashes through install. I managed to install 10.3.5 as long as I would move the mouse the installer wouldn't crash. However when in the OS it crashes when applying a combo update or crashes periodically. I have tried putting all the original pieces back in the computer; the HDD, the Ram, and the Graphics Card; it seemed like it was working but again, crashed. I also ran AHT, everything is "fine". I am extremely stumped as to what it could be. Any help is appreciated.

(Edit) Solution in reply #2

 

[Fami7455]

Those G5s have chipset heatsinks behind the motherboard which are held with plastic pins of subpar quality. Eventually (Usually in the summer, because of the heat), the pins will break, dislodging the heatsink and making the chipset overheat after a short amount of time. In the best of cases, the computer simply crashes or freezes, and gets shut down by the user. In the worst cases, this issue goes unnoticed, the chipset goes into thermal runaway and beraks its solder joints or fries itself. I've had five G5s brought to me which presented this issue, three of them had fried chipsets.
If yours hasn't fried itself (I'd say it probably hasn't, since it boots reliably and crashes later), I'd say take out the logic board and check for broken heatsink pins. They can (and should, even if they're not broken) be replaced with screws and locknuts, keeping the original springs.

EDIT: Here's a great guide on how to replace the pins: https://www.thinkclassic.org/viewtopic.php?id=106

 

[Hughmac]

My guess is bad RAM somewhere. Have you tried reseating the modules or swapping them out for others?

Cheers

Hugh

 

[daveyanthony]

Those G5s have chipset heatsinks behind the motherboard which are held with plastic pins of subpar quality. Eventually (Usually in the summer, because of the heat), the pins will break, dislodging the heatsink and making the chipset overheat after a short amount of time. In the best of cases, the computer simply crashes or freezes, and gets shut down by the user. In the worst cases, this issue goes unnoticed, the chipset goes into thermal runaway and beraks its solder joints or fries itself. I've had five G5s brought to me which presented this issue, three of them had fried chipsets.
If yours hasn't fried itself (I'd say it probably hasn't, since it boots reliably and crashes later), I'd say take out the logic board and check for broken heatsink pins. They can (and should, even if they're not broken) be replaced with screws and locknuts, keeping the original springs.

EDIT: Here's a great guide on how to replace the pins: https://www.thinkclassic.org/viewtopic.php?id=106

You were spot on, I removed the logic board and the heatsink clips had worn out/broken; Would've fallen off when I took it out if it weren't for the screws. Thanks so much for your help, and I'll post again if this fixes my problem.

 

[daveyanthony]

I am testing the computer right now, no crashes so far... On another note, I bent some of the pins in my one socket on accident; I tried to fix them but no dice. I am now running on a single 2GHz G5 which is not a problem but I would like to get both running again. I know the cpu's are fussy about being in the same config, so if I were to get a same model logic board would they work well together? Or would I get the loud uncalibrated mess? Thanks.

 

[eyoungren]

On another note, I bent some of the pins in my one socket on accident; I tried to fix them but no dice.

You can use a jeweler's screwdriver to fix those. These are small enough to slip in between pins and allow you to push them back up straight.

I've used them to straighten the pins on my G4's CPU socket before when I bent them.

This is what they look like…

 

[daveyanthony]

You can use a jeweler's screwdriver to fix those. These are small enough to slip in between pins and allow you to push them back up straight.

I had tried a small screwdriver to fix them earlier but they are so small and so hard to see, I couldn't tell if I had gotten them straight or not. I tried using the telephoto on my iP7+ which helped a little bit but I suppose I'll just have to get into a good spot to work on them for a while. If I still can't get them right would I be able to use a same model logic board? They're fairly cheap online refurbished for the model I have (820-1592-A). Thanks.

 

[eyoungren]

I had tried a small screwdriver to fix them earlier but they are so small and so hard to see, I couldn't tell if I had gotten them straight or not. I tried using the telephoto on my iP7+ which helped a little bit but I suppose I'll just have to get into a good spot to work on them for a while. If I still can't get them right would I be able to use a same model logic board? They're fairly cheap online refurbished for the model I have (820-1592-A). Thanks.

Before you spend cash over an otherwise functioning board I might make one more suggestion - a magnifying glass. Lots cheaper than a new LB.

 

[backyardvoodoo]

Is the PMG5 meant to be able to power on with 1 CPU removed? I tried booting mine with the top CPU only and it wouldn't react to the power button

 

[Jubadub]

Those G5s have chipset heatsinks behind the motherboard which are held with plastic pins of subpar quality. Eventually (Usually in the summer, because of the heat), the pins will break, dislodging the heatsink and making the chipset overheat after a short amount of time. In the best of cases, the computer simply crashes or freezes, and gets shut down by the user. In the worst cases, this issue goes unnoticed, the chipset goes into thermal runaway and beraks its solder joints or fries itself. I've had five G5s brought to me which presented this issue, three of them had fried chipsets.
If yours hasn't fried itself (I'd say it probably hasn't, since it boots reliably and crashes later), I'd say take out the logic board and check for broken heatsink pins. They can (and should, even if they're not broken) be replaced with screws and locknuts, keeping the original springs.

EDIT: Here's a great guide on how to replace the pins: https://www.thinkclassic.org/viewtopic.php?id=106

What an absolute savior. Does this also apply to the Quad-core models? Though the creator of that thread you linked to speculates this issue is a lot less likely to happen in the dual-core and quad-core models, but he didn't know for sure, so I ask.
I'll definitely keep this in mind as the years go by.

So far, my Quad only EVER crashed because of bad, cheap RAM modules. I used to operate with 16GB of RAM, but now only half of the sticks are detected, and so now there's "only" 8GB. Reseating the sticks or trading places with one another sometimes would get 16GB to be detected again, but the system becomes crash-prone. But when I just left it at 8GB without touching those sticks again, my G5 has NEVER crashed since. It's been two years since, and still counting.

Of course, I'd rather buy 16GB of RAM all over again (higher quality RAM this time) and replace them all, but, sadly, I don't currently meet the financial conditions to do that. Although it's not like it's even easy to get close to using 8GB of RAM there, even if I deploy RAM Disks.

Incidentally, these were the sticks I bought and have (read: avoid them): https://www.amazon.com/DDR2-533-PC2-4200-Memory-Upgrade-Certified/dp/B009ORANZW
Note: When I purchased this originally, they used a different logo, product name/brand and product picture, but this is the same product URL as the one from which I purchased in 2017. Changing the branding that way feels suspicious to me, but what do I know...

 

[Fami7455]

I am testing the computer right now, no crashes so far... On another note, I bent some of the pins in my one socket on accident; I tried to fix them but no dice. I am now running on a single 2GHz G5 which is not a problem but I would like to get both running again. I know the cpu's are fussy about being in the same config, so if I were to get a same model logic board would they work well together? Or would I get the loud uncalibrated mess? Thanks.

As @eyoungren said, try a small screwdriver and a magnifying glass. Another cheap alternative to an entire logic board would be a set of dentistry tools, in particular a probe and a mirror.

Is the PMG5 meant to be able to power on with 1 CPU removed? I tried booting mine with the top CPU only and it wouldn't react to the power button

Seems to be hit and miss, in my experience some machines boot up with a single CPU installed in the top socket while some present the behavior you described. I don't know if there's a correlation between this and the model.

What an absolute savior. Does this also apply to the Quad-core models? Though the creator of that thread you linked to speculates this issue is a lot less likely to happen in the dual-core and quad-core models, but he didn't know for sure, so I ask.

I don't have experience with the PCI express models, so I'm not sure if the pushpins are as likely to fail as on the PCI and PCI-X models. I guess replacing them with screws just in case wouldn't hurt, though.

 

[daveyanthony]

I apologize for the frustration my question about the logic board may have caused.... I'm a bit of an over reactor, and I like to have a plan B in place... I am pleased to say I was able to fix the pins on the logic board with some patience and tiny screwdrivers*. However the computer still seemed to crash after the mounting fix, albeit not as often; I applied some new thermal paste to to it while it was out again and hopefully that will prevent further crashes. Thanks all for the help.

(Edit) Just saw the post about PMG5 booting with only one CPU, mine did boot, however the processor that was working was the one in the top slot.

(Edit 2) *Very odd, I did a clean install of Tiger and it loaded up saying 2 CPU's. After updating it to 10.4.11 it restarts and only registers 1 CPU. I may have to take it out again and do more fiddling.

 

[Fami7455]

I apologize for the frustration my question about the logic board may have caused.... I'm a bit of an over reactor, and I like to have a plan B in place... I am pleased to say I was able to fix the pins on the logic board with some patience and tiny screwdrivers*. However the computer still seemed to crash after the mounting fix, albeit not as often; I applied some new thermal paste to to it while it was out again and hopefully that will prevent further crashes. Thanks all for the help.

(Edit) Just saw the post about PMG5 booting with only one CPU, mine did boot, however the processor that was working was the one in the top slot.

(Edit 2) *Very odd, I did a clean install of Tiger and it loaded up saying 2 CPU's. After updating it to 10.4.11 it restarts and only registers 1 CPU. I may have to take it out again and do more fiddling.

That's strange. Was the bottom socket the one which received the damage?

 

[daveyanthony]

That's strange. Was the bottom socket the one which received the damage?

Yes the bottom socket was damaged.