iMac G4 constantly crashing/kernel panics

[indigo_k]

So, I've had this iMac G4 for more than a year now. When I got it they said it was water damaged and wouldn't start. I figured out the power supply was blown so i installed a replacement and got it working. I later maxed out the RAM, added an Airport card, replaced the PRAM battery, and swapped the 80GB HD with a 500GB SSD (properly partitioned). I currently have OSX Tiger on one 8gb partition, MacOS 9.2.2 (MacOS9 Lives edition) on another 8GB partition. I prefer to boot into OS 9, but have been in Tiger more lately as I'm trying to figure out what is causing this.

What happens is that, before about 2 hours of use (frequently much less) the machine will just completely freeze up while in OS9, or kernel panic while in OSX. It is inconsistent what I'm doing with the machine, what apps are running. I could be listening to music, moving files, reinstalling the OS, or even just trying to boot the machine. It doesn't matter what I'm doing, or if I even have any applications running other than the Finder, it will reliably become unresponsive before too long.

Now, I remember using both these operating systems when they were new, and am aware that they were prone to crashing often, but nothing like this. The unreliability of the machine has made it impossible to enjoy firing it up to play with it, as I know that I'll inevitably end up trying to troubleshoot this.

I have both MacsBug and Conflict Catcher looking out for issues on the OS9 side, but both have been coming up clean. I've reinstalled both OSes multiple times. Considering that the crashes happen on both OS9 and OSX I worry that it may be a greater hardware issue. I've been making sure that I reapply the thermal paste every time I open it up. I have not touched or replaced the fan yet, but have considered it. And I know the DVD drive is faulty and could stand to be replaced. What other hardware issues should I be on the lookout for here? I mentioned that it was water damaged, but I don't see any obvious corrosion on the logic board, no leaking caps, or anything like that. But maybe I'm not looking closely enough? Man, I just don't know. I'm a little at my wit's end here.

 

[phunguss]

Have you removed the motherboard and looked at the bottom side as well? Try removing one of the sticks of ram (DIMM or SODIMM) and see if you get the same crashing, then reinstall and remove the other one and try again.

 

[indigo_k]

Have you removed the motherboard and looked at the bottom side as well? Try removing one of the sticks of ram (DIMM or SODIMM) and see if you get the same crashing, then reinstall and remove the other one and try again.

I don't remember if I did pull the motherboard out entirely or not. I feel like I started to but it ended up being a lot more complicated than I was expecting? Or maybe I did. Really don't remember. I'll go ahead and try that when I replace the thermal padding on the CPU, which I'm pretty sure I have not done yet.

 

[jibsaramnim]

If you are using an adapter to connect your SSD, it might also be worth trying to see if using a different adapter or SSD makes a difference. If you have no other adapters and a working IDE HDD, it might be worth switching to that just to see if it makes any difference.

Slightly unrelated, but out of curiosity, could you tell me what replacement power supply you got?

 

[indigo_k]

If you are using an adapter to connect your SSD, it might also be worth trying to see if using a different adapter or SSD makes a difference. If you have no other adapters and a working IDE HDD, it might be worth switching to that just to see if it makes any difference.

Slightly unrelated, but out of curiosity, could you tell me what replacement power supply you got?

I don't have another adapter or SSD, but I guess I could put the original drive back into it.

The power supply I got off eBay, it had been pulled from another iMac G4. I assumed that since there were so few of these models iterated that they would be interchangeable.

 

[jeffburg]

its hard to say. Usually freezing like that sounds like a RAM issue. Especially if it's so consistent. When you said you maxed out the ram, did you max it to the unofficial max or the official max? But that would be the first thing I would go for is to remove half of the ram (like the user accessible one) and then see if it still crashes. If no, then put that stick back in and remove the other one and see if it continues to crash.

In OS X you can read the kernel panic logs in Console.app and it might point you somewhere. The problem is ram crashes usually look random. But if it's something else like the video card or ata controller, you will get more consistent crashes that point to some KEXT crashing.

But in general, you strip the machine down to the bare minimum and see if it still crashes. That could include removing the airport card. You could even unplug the CD Drive and the Hard Drive and then boot from an external firewire drive to see if the ATA controller is causing crashes.

If you have the ability to burn a CD on a different Mac, you could also run Apple Service Diagnostic. This will do a thorough RAM check and it can also check most of the other components of the system. Guessing because your system boots OS 9 that it will actually be the older diagnostic called MacTest Pro. I have never used this software so I am not sure how good it is. But I assume it also has some sort of thorough RAM check.

All Apple Hardware Test (AHT) & Apple Service Diagnostic (ASD) disks - Macintosh Repository

Apple Service Diagnostic (ASD) is Apple's bootable hardware testing console that lets you run extensive technical test routines on your...

www.macintoshrepository.org

 

[jeffburg]

Oh yeah, and the other thing I forgot about is that if you did open the machine, did you reapply thermal paste to where the heat sink connect to the upper shell of the case?

Or I guess, can you relate the timing to when the crashes started to right after you worked on it? Or was it months later?