PowerMac G5 attempts to boot, then hangs and goes insane

[NelizMastr]

Good morning lads and lasses,

 

My Power Mac G5 I have laying around has developed an interesting problem in the course of it's life. I picked this one up for free

since the previous owner lost the power cable and couldn't test it.

 

The problem is that it won't boot from any medium you throw at it. It will simply hang at the Apple boot screen. No spinning wheel, no kernel panics. The fans go insane once it

hangs. So far, I've tried a different PRAM battery (probably another dead one, new one will be tested later today) to no avail, different harddrives, a different DVD drive and different

DVDs (Tiger 10.4.6, Leopard 10.5.6, both are universal images for both PPC and Intel). I've even tried partitioning the drive on my Mac Pro and restoring the DVD to one of the partitions.

Again, to no avail.

 

Things that I'm still considering:

 

- brand new PRAM battery (already have one laying around)

- PCI SATA card to make sure it's not the onboard SATA controller.

 

Any other ideas that are not related to the HDD / DVD drive? It's a 2004 G5 model with dual 1.8Ghz G5s and 2x 1GB of PC3200 RAM and a Radeon 9600XT.

 

EDIT:

 

The system will show the Finder question mark icon when no boot device is available (no HDD/ODD) and it will respond to the option key. It won't respond to single-user mode, safe mode, verbose mode or PRAM reset commands or hotkeys however.

 

EDIT2:

 

Replacing the PRAM battery with a brand new one didn't solve anything. Still no boot. A PCI SATA card, same story, no boot, still hangs at the Apple logo.

 

*sigh* is there anything left that could cause this annoying problem?

 

EDIT3:

 

Some more in depth investigation yielded the following results:

 

- Booting into the open firmware itself works

- entering the multi-boot environment there works

- Doing a quick memory check from the command line yielded positive results. memory appears OK.

 

It seems the Mac will load the firmware and parameters, but as soon as it starts to load a kernel, it crashes.

 

Apple Hardware Test was obtained and burned to a disc. This will be tested later today to see where the errors start popping up.

Edited April 23, 2015 by NelizMastr

[Big Ans]

did you try to boot in safe mode? cmd + shift + p +r

or just the shift key

[NelizMastr]

The thing is, it won't respond to any hotkeys once it attempts to boot. It hangs right away. PMU reset didn't do anything, PRAM reset didn't do anything either (again, might be resolved by fitting a new PRAM battery).

[simson0606]

if you try to boot without any bootable media (hdd, odd, usb) do you see the error icon?

[NelizMastr]

if you try to boot without any bootable media (hdd, odd, usb) do you see the error icon?

 

It will show the well known question mark icon which keeps flashing until it finds a bootable medium. 

[brownninja97]

max fans normally mean motherboard drivers have failed which normally means bad motherboard which commonly means a capacitor is dying or dead. At least its like that with windows pcs, ive got no experience with macs so it may react differently.

[NelizMastr]

Fan speed is partially stored in PRAM on a Mac, so a new PRAM battery might fix it. In some cases, Apple needs to manually reset a specific controller which requires software only available to Apple engineers. The logic board itself is perfectly fine, it completes the POST without any problems (confirmed by the chime).

[simson0606]

after some googling, i think you have to replace the battery before you can boot successfully, and i'd imagine it will then respond to the shortkeys again

[Sauron]

Do you have any way to access the bios? Or is that locked in macs?

 

Have you tried popping the hdd in another computer to make sure the data on it is not corrupt, or if the drive is actually still functional?

[NelizMastr]

Do you have any way to access the bios? Or is that locked in macs?

 

Have you tried popping the hdd in another computer to make sure the data on it is not corrupt, or if the drive is actually still functional?

 

There is no such thing as a BIOS on a Mac. It boots directly to Open Firmware on PowerPC, which loads the pre-boot environment and uses the PRAM to determine which settings to apply and which device to boot. The harddrive is not an issue, as I've tested multiple drives (even a brand new Kingston HyperX SSD) to no avail. A DVD won't boot (on IDE interface) so the harddrive can't be linked unless the south bridge is knackerd.

[NelizMastr]

after some googling, i think you have to replace the battery before you can boot successfully, and i'd imagine it will then respond to the shortkeys again

 

Will try the new PRAM tonight.

[RossMadness]

Have you tried running AHT? For PowerMacs, I think the diags are on the OS Disc itself. Alternately, if you can plug it in using an ethernet cable then hold Option+D, that will do online diagnostics. It might be worth a shot to see if that brings up any error codes after the tests run. Honestly, I haven't tried this on a PowerMac, but I have done it on the newer Macs at work.

[NelizMastr]

Have you tried running AHT? For PowerMacs, I think the diags are on the OS Disc itself. Alternately, if you can plug it in using an ethernet cable then hold Option+D, that will do online diagnostics. It might be worth a shot to see if that brings up any error codes after the tests run. Honestly, I haven't tried this on a PowerMac, but I have done it on the newer Macs at work.

 

Thanks for this suggestion. This was a pickup machine and didn't come with any manuals discs or anything, not even a power cable. Not sure if PowerMacs actually have online diagnostics. Online diagnostics and Online Restore weren't a thing until 2011 or 2012 I think, so I doubt it will work, but thanks nonetheless.

[NelizMastr]

Updated the post. PCI SATA card and a new PRAM didn't solve the problem. It still won't allow a PRAM reset, and it still hangs as soon as its supposed to boot.

[NelizMastr]

Some more in depth investigation yielded the following results:

 

- Booting into the open firmware itself works

- entering the multi-boot environment there works

- Doing a quick memory check from the command line yielded positive results. memory appears OK.

 

It seems the Mac will load the firmware and parameters, but as soon as it starts to load a kernel, it crashes.

 

Apple Hardware Test was obtained and burned to a disc. This will be tested later today to see where the errors start popping up.