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What to see when buying a used PowerMac G5?

Hello there.

Tomorrow I'm buying a used PowerMac Quad G5 with 7GB of RAM and a Quadro FX 4500 for music and foto editing for about 200€ (and it comes with the original keybord and mouse plus Leopard and Logic 8, so it's a GREAT deal).

Since this line of Macs as some known issues, I was wandering what I should look in the machine. The seller says that the machine was seen by an Apple technician and that everything is OK, but today you never know, specially since this is an authentic bargain.

BTW, I could I do the equivelant of the AHT in the PowerMac to see if the seller is not lying?

PowerMac, Mac OS X (10.5.8), Quad G5, 7GB RAM, Quadro FX 4500

Posted on Jun 18, 2012 6:28 PM

30 replies

japamac

Level 7

24,400 points

Jun 19, 2012 5:14 PM in response to Leite

The following discussion may be of interest to you:

https://discussions.apple.com/thread/3332855?tstart=0

Leite Author

Level 1

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Jun 20, 2012 9:44 AM in response to japamac

Well, one thing that I read of a guy having a problem almost like mine was that the B core of his CPU B was overheating, making the hole CPU reach temperatures like mine and hanging the computer. His problem was that the thermal mass wasn't covering his core B, making it overheating. Since this computer is already 7 years old, I was wandering if it isn't my thermal mass that needs to be replaced.. What do you think?

Leite Author

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Jun 20, 2012 3:23 PM in response to japamac

I've a problem. I wanted to run that command but I don't know the admins password (neither the seller, this computer was a gift from his music studio and he almost didn't knew how to work with the computer) and when I try to boot from the install disk the system hangs. Any ideas?

japamac

Level 7

24,400 points

Jun 20, 2012 3:26 PM in response to Leite

The thermal compound and connection are always worth investigating.

Thermal compounds were made to last 3-5 years, so replacement is warranted after these many years.

Reseat of the processors is also a troubleshooting step, so removal of the processors, replacement of the thermal compound and reseat of the processors is worthwhile.

Use Arctic Cooling MX-4. Safe (electrically neutral), high thermal conductivity and 8 year life.

Leite Author

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Jun 20, 2012 4:03 PM in response to japamac

I found a computer store close to me with that compound. 4g would be enough for the 2 CPUs? Also, do I need to buy a special thermal mass remover to remove the remainings of the old one?

japamac

Level 7

24,400 points

Jun 20, 2012 4:20 PM in response to Leite

4g. is plenty. You can do several machines with 4g.

do I need to buy a special thermal mass remover to remove the remainings of the old one?

Not really.

After wiping the processor chip and heatsink pad with a dry cloth to remove the bulk, I remove the remaining residue with alcohol (isoprophyl).

Non-acetone nail polish remover also works well to remove the residue and is safe for the components.

Leite Author

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Jun 20, 2012 5:21 PM in response to japamac

I never did any, so that's why I'm asking..

The only alchool that I have is ethyl alcohol 96%. Tomorrow I'll go supermarket or to the pharmacy on my way to the computer store.

Thank you for your help. You've been amazing.

japamac

Level 7

24,400 points

Jun 20, 2012 11:11 PM in response to Leite

I never did any, so that's why I'm asking..

Asking is a smart way to learn.

I have a general thermal compound tutorial on my site:

9AE7FE0E-0CF2-4A7C-8003-489B282582BC.html

Save a PDF copy of the manual that I linked (previously).

It will be invaluable in helping get you through the disassembly and reassembly of your machine.

Leite Author

Level 1

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Jun 21, 2012 8:12 AM in response to japamac

Is it alright to use ethyl alcohol 96%? I don't know where to find isoprophyl...

japamac

Level 7

24,400 points

Jun 21, 2012 3:34 PM in response to Leite

That will probably be fine.

Just moisten a small portion of a cloth with it, then rub the residue off the surfaces.

Leite Author

Level 1

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Jun 21, 2012 3:41 PM in response to japamac

They had a special product for removing thermal mass in the store, and it has cheep, so I prefered to buy it. Tonight I don't have any help to remove de CPUs so I'm doing it tomorrow.

Is there any way to disable the problematic CPU in open firmware? I would really like to try the beast... :/

japamac

Level 7

24,400 points

Jun 21, 2012 3:58 PM in response to Leite

Yes.

Turn on the G5 while holding down Command-Option-O-F

At the command promt, type setenv boot-args cpus=1
Press Enter.

Then type mac-boot

Press Enter.

Leite Author

Level 1

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Jun 21, 2012 4:13 PM in response to japamac

And what I would run to re-enable it?

Leite Author

Level 1

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Jun 21, 2012 4:48 PM in response to Leite

nvram-reset

or just reboot pressing Cmd-Opt-P-R. I'm I right?

japamac

Level 7

24,400 points

Jun 21, 2012 4:53 PM in response to Leite

setenv boot-args

Or, you can also reset the NVRAM:

reset-nvram

Enter

reset-all

Enter

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What to see when buying a used PowerMac G5?