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View Full Version : iMac kernel panics + corroding hardware: related?




stereocilia
Jan 28, 2011, 05:22 PM
I've run into an iMac that is having a variety of problems.
iMac 8.2 (G5) from around 2005

-On some boots the screen is blank and the system beeps three times, then the fans run full blast and nothing happens.

-Some boots will give the classic kernel panic screen over the apple logo (white screen) and stop.

-Occasionally the system will boot, but a black box appears centered in the screen and says you must restart by holding the power button down.

-If I try to reinstall the OS, I get to various parts of the installation, but it always freezes or has the black box error before the install can finish.

-The fans turn on full blast after almost every freeze, crash, or failure. (don't know if this is typical.

What I've already tried:
-Reseting PRAM
-Reseting NVRAM
-Reset-all through open firmware boot
-Used two different sticks of RAM from a working system, with the same results
-Tried a brand new hard drive + different RAM with same results
-Boot with only RAM, no hard drive. Boot to installation disc. This results in kernel panics on boot, or as the install disc is load. It shows a blank black box in the center of the screen. Occasionally, it just freezes.

After inspecting the system for damage, I found a couple of parts that were corroding. See the images below

This is the cpu heat sink. The fins are corroding where they attach to the main plate.
Educated guess:
I'm thinkin' maybe the corrosion impedes the ability to properly cool down the cpu, causing the system to have errors, and turn the fans on.
Question for my forums peeps:
Do you think that this corrosion is part of my problems?
http://img692.imageshack.us/img692/2028/cpuheatsinkcorrosion.jpg

These parts are next to the CPU. They're leaking through the top. After I scraped off the leakage, I noticed the tops of the components are not level like the others. It looks like when you stick a soda in the freezer and the top explodes. Like there was a lot of pressure inside and it tried to escape. Ok, it doesn't look as bad as an exploded soda can, but it doesn't look like it's sister components. The tops look like the letter 'K' and the leakage is from the center of the 'K'.
Question for forum:
Do you think this is part of my kernel panic / freezing problems?
http://img88.imageshack.us/img88/6991/leakage1.jpg
http://img266.imageshack.us/img266/5135/leakage2.jpg



MiBook84
Jan 28, 2011, 06:28 PM
It is a known issue that some iMac G5 has bad capacitors. They start to leak and that makes your computer crash. They need to be replaced. I think Apple fixed it for free for a while but I am not sure since it is such an old computer now. If you google iMac G5 capacitor you will find lots of tips and help.

chris98vf
Jan 28, 2011, 06:39 PM
if you've got decent soldering skills it can be fixed easily but if you don't it could be costly to fix to pay someone. For the age it may be worth finally upgrading. You can sell it as is on eBay and get about $150ish.

MiBook84
Jan 28, 2011, 06:40 PM
if you've got decent soldering skills it can be fixed easily but if you don't it could be costly to fix to pay someone. For the age it may be worth finally upgrading. You can sell it as is on eBay and get about $150ish.

I agree! By the way, why do you have lots of iMacs in your basement? :D

chris98vf
Jan 28, 2011, 07:13 PM
I agree! By the way, why do you have lots of iMacs in your basement? :D

I buy broken ones, repair them and resell...

stereocilia
Jan 28, 2011, 07:17 PM
Thank forum peeps! Those are some very helpful answer, I really appreciate it.

I'm going to try and replace those leaking parts.
I'll report back and let you know how it went.

MiBook84
Jan 28, 2011, 07:17 PM
I buy broken ones, repair them and resell...

Ah, I see! I have a white 24" iMac with graphics issues, have you been working on that model? I think it is the gpu and I am thinking about taking it out and cleaning up the thermal grease and replace it. And if it doesnt work Ill have to buy a new gpu-card I guess.

stereocilia
Jan 28, 2011, 07:19 PM
I agree! By the way, why do you have lots of iMacs in your basement? :D

MiBook84: My mac doesn't have cob webs on it! :D. This iMac belongs to a family friend that rarely uses it. Her and her husband thought it broke because they didn't use it enough! Like an old car that sits, and you have to start every now and again to keep everything moving. Thanks for the reply.

chris98vf
Jan 28, 2011, 07:20 PM
Ah, I see! I have a white 24" iMac with graphics issues, have you been working on that model? I think it is the gpu and I am thinking about taking it out and cleaning up the thermal grease and replace it. And if it doesnt work Ill have to buy a new gpu-card I guess.

I don't want to go too far off the original topic but here's a link you might be interested in for your 24"
http://www.ifixit.com/Answers/View/3349/Is+it+possible+to+replace+the+graphics+card+into+a+better+one

MiBook84
Jan 28, 2011, 07:22 PM
MiBook84: My mac doesn't have cob webs on it! :D. This iMac belongs to a family friend that rarely uses it. Her and her husband thought it broke because they didn't use it enough! Like an old car that sits, and you have to start every now and again to keep everything moving. Thanks for the reply.

:) I see! Strange to see that corrosion anyhow, havent seen that on any models besides the water-cooled Power Mac G5s before. Perhaps it is the "goo" from the capacitors that have leaked down on the heatsink.

MiBook84
Jan 28, 2011, 07:23 PM
I don't want to go too far off the original topic but here's a link you might be interested in for your 24"
http://www.ifixit.com/Answers/View/3349/Is+it+possible+to+replace+the+graphics+card+into+a+better+one

Ops sorry, its too late here in Sweden and I easily go off-topic then :) Thanks for the link!

chris98vf
Jan 28, 2011, 07:27 PM
Ops sorry, its too late here in Sweden and I easily go off-topic then :) Thanks for the link!

hehe, yeah, it's not hard. I just sent you a PM that we can continue off topic lol

Trdinput
Jul 12, 2011, 02:48 AM
I have a G5 2.7 dual made in September 05. It hangs like a horse thief. Some of the forums offer great advice but it appears to be outdated. I was sitting around thinking with a friend what if it's a temperature sensor problem? Based on the amount of dirt removed from this e bay machine, it would not surprise me. I thoroughly checked the LCS, reset pram, nvram, reset all, replaced the ram, reset the smu, put in a I.5 ter hd, even trashed start up items suggested in one forum, and used target disk mode to accommodate the searching, finding and trashing.

Call me crazy, but I decided to put a box fan blowing through the system. Before I did this, there were kernel panics, screen freezes, the wheel of death etc. Now, with the box fan, it runs beautifully. I have written zeros and reinstalled 5 times. I am done for now, too much time spent on an eBay computer. It does stand to reason to wash the boards in warm soapy water to alleviate the misread sensor readings. I sh?t you not, if you take the machine completely down and gently use a soft tooth brush,and put it back together, completely with a micron of moisture, it will work. Get these darn dirty machines cleanedvup and theybwill stop the nonsense.

One shot, one kill

Trdinput