kernel panic and DIMM0 error

[Crrisssy]

I'm having crazy kernel panics on my 1GHz iMac G4, every 15 mins or so. There was a power outage and it wouldn't boot up (stuck on gray screen) so the MacGenius wiped my hard drive and reloaded 10.3.5 (yeah I had 10.3.9 - old stuff). Before the MacGenius got to it, the Hardware extended test showed no memory failures, but now the Hardware test shows: memory error detected, 2 MEM/1/4: DIMM0/J22.

I can't get the software update to run, but the kernel panics happened when I had the latest updates (for the 10.3), so I don't think thats the issue (but another issue).

I have had the computer open before so I'm comfortable with crackin it open, but if I were to pull one of the ram cards, which one is DIMM0 ? Is there a way to tell?

Is the ram bad? Is this causing my kernel panics?

[hughvane]

Originally Posted by Crrisssy

I'm having crazy kernel panics on my 1GHz iMac G4, every 15 mins or so. I have had the computer open before so I'm comfortable with crackin it open, but if I were to pull one of the ram cards, which one is DIMM0? Is there a way to tell? Is the ram bad? Is this causing my kernel panics?

The error message suggests a bad RAM stick, or one that has been unseated. The two RAM slots are numbered, the digit appearing at one end of the slot. I would suggest that you swap the RAM sticks, making sure they're both seated properly, and then try a Reboot. Please post back to report progress (or not).

[gehrbox]

Originally Posted by hughvane

The error message suggests a bad RAM stick, or one that has been unseated. The two RAM slots are numbered, the digit appearing at one end of the slot. I would suggest that you swap the RAM sticks, making sure they're both seated properly, and then try a Reboot. Please post back to report progress (or not).

You can only access one of the ram sticks in the G4 iMac, the other is buried on the other side of the system board. It would require a good bit of disassembly to access. Just remove the one that is accessible from the base and that will tell the tale. If its the internal ram that has failed get ready for some labor charges or do some research on how to disassemble the dome.

[hughvane]

See if this helps: http://www.youtube.com/watch?v=ZsaHf-nfgt4

[Sun Baked]

I looked at http://developer.apple.com/documenta...p03/index.html

The iMac has two RAM expansion slots: one for an SO-DIMM (referred to as J22 in the System Profiler) and one for a DIMM, which is preloaded by the factory (referred to as J20 in the System Profiler). The iMac has 184-pin, 8-byte, DDR333 (PC2700) SO-DIMM (small outline, dual inline memory module) that uses DDR SDRAM devices The expansion slot capacity is an additional 512 MB, supporting a maximum of 1 GB.

The user SO-DIMM, so you might just be able to pull the laptop sized DIMM and see if the problem goes away.

iMac (Flat Panel) and iMac (17-inch Flat Panel): Installing or Replacing Memory

[Crrisssy]

Well there were no markings to tell which RAM was which. Turns out, the DIMM0 is the one that is easily accessible by removing the base access panel per the User's Guide. I pulled it and HURRAY! No more kernel panics. Prob fixed - but tooo slow with just 512MB.

This RAM stick is the same size & specs as my iBook ram so I pulled that stick out (also 512 MB) and replaced the bad one. The iMac can only handle 2 512 sticks but I can get a new 1GB stick for my G4 iBook, and its only $8 different in price (on crucial dot com - recommended by Genius Bar dude).

Hey, btw the other iMac stick of RAM is also easy to access on this machine. You just have to pull the bottom off the machine with 4 larger bolts that require a T15 star tool (any1 who has a jeep, has these). These bolts are visible after you have the airport card / extra ram slot access panel off. The bottom of the machine comes off, no tricks. Good to clean the dust bunnies out! Whew, there were tons of em! This RAM stick is different shape/size and luckily mine was fine.

THANKS FOR THE HELP FOLKS!

[gehrbox]

Originally Posted by Crrisssy

Hey, btw the other iMac stick of RAM is also easy to access on this machine. You just have to pull the bottom off the machine with 4 larger bolts

Did you scrape off the old and apply fresh thermal paste to the heat sink when you put it back together?

If you neglected to do it you might consider going back in to perform this step.

[Sun Baked]

Originally Posted by Crrisssy

Hey, btw the other iMac stick of RAM is also easy to access on this machine. You just have to pull the bottom off the machine with 4 larger bolts that require a T15 star tool (any1 who has a jeep, has these). These bolts are visible after you have the airport card / extra ram slot access panel off. The bottom of the machine comes off, no tricks. Good to clean the dust bunnies out! Whew, there were tons of em! This RAM stick is different shape/size and luckily mine was fine.

THANKS FOR THE HELP FOLKS!

Yep the user accessible small one is the SO-DIMM -- this is laptop memory and why Apple calls the SO-DIMM small outline. Mainly why your laptop memory fit inside.

The big one inside is the cheaper desktop memory.

Which is why I highlighted Apple marking the DIMMO and the SO-DIMM.

[Crrisssy]

Just saw this old post and thought I'd add...

It's 2010 and I still haven't been able to kill this computer! I still use it daily. It sits on my desk in my office and is as reliable as ever. I haven't needed a new computer in 5 yrs but my loving spouse goes thru PC after PC...