A couple of people asked me to start a new thread on Kernal Panics & random shutdowns specific to PPC DP 2 Ghz G5's. I am by no means any kind of guru or technician. I try to be methodical and careful whenever I open my G5. I fully realise that I have voided my warranty several hundred times
but my g5 is well and truly out of warranty so that is a non issue.
G5 Kernel Panics & Random Shutdown Analysis
From my own personal experience of being driven by desperation by random shutdowns and kernel panics to disassemble my G5 I have managed to form opinions on the possible and probable causes.
I strongly feel now that a combination of one or more of the elements listed below, occurring singly or simultaneously is the most likely cause of kernel panics or random shutdowns.
Besides adding an extra internal case fan, swapping the seating order of the PSU fans and adding a perorated PCI slot backplane I have not performed any other modifications to my G5.
Suspected Contributing Factors :
(EDITED : Oct. 2007
0.Badly seated CPU units.
1. Overheating caused by poor air circulation.
2. (related to above) Accumulated dust in and around the CPU cooling units and power supply.
3. Bad OSX & update-management.
4. Bad memory & PCI Cards.
5. Bad hard drives that do not show errors in Disk utility.
I'll deal with each in turn except #1 and #2 which are related.
O. Badly Seated CPU Units
I made a page specifically for this problem. : http://www.hatsuon.net/macstuff/G5_TAKE ... _2Ghz.html
1. & 2. Overheating and Dust
Hardware Monitor :
Marcel Bresink regularly updates this wonderful app. Buy a license and set it up to display the most crucial temp readings on your desktop. It runs with a very low memory/CPU overhead.
If you live in a country with hot summers or you are a smoker then you have to think twice about where you place your G5. Never place it on or near the floor, all of those thousands of little holes in the G5 case work like vacuum cleaners when it's working hard.
Install an extra fan
: I purchased a low db fan with an eye to moving as much air as possible. I mounted it just inside the front of the G5 case, above the memory DIMM slots. I ran a "Y" power line from the DVD drives power line. The Memory Heatsink Controller used to show 72.5°C (165°F) or higher, it now hovers around 61°C (141°F), a vast reduction. Remember that your G5 will shut down rather than fry a CPU or other vital component. Your PSU will simply overheat and blow if it overheats and your G5 will be dead but rather than pay Apple $400+ to replace a PSU you can buy them on the net (Google "G5 PSU") and install it yourself using my guide below.
Install perforated PCI slot backplanes:
Hunt around the PC parts shops. I have just done this this week and have noticed a slight reduction in temperature readings in this area of the case. having these extra 46 holes near my PCI slots complements the extra fan I installed in ramping up the amount of hot air shifted out of the case.
Blow out the obvious dust
: Use canned air and blow out the obvious areas of the case. NOTE:
Don't turn these compressd air cans upside down, they then blow out super cold air which could fracture dellicate soldering traces.
Don't forget to check all of the little holes on the front & rear of the case.
remove as many fans as possible and "polish" them, even rub them down with "ArmourAll"; a shiny, clean surface will accumulate dust much slower than a hastily wiped fan surface. think of airplane propellors.
Remove and de-dust your power supply & CPU cooling units
: I put up a guide here http://www.hatsuon.net/macstuff/G5_TAKE_APART/Disassemble_G5_DP_2Ghz.html
. It is not for the the technically incompetent but if you have installed a DVD or hard drive then it is do-able with care and almost guaranteed to yield better overall performance.
During the dismantling of my G5 I found one of the bolts that hold down the CPUs to the motherboard lying loose in the case after an Apple tech here in Japan had replaced a blown PSU. Apple technicians are not infallible.
3. Bad OSX & update-management:
If you are truly serious about removing the possiblity of future kernel panics then you will now back up your important data and from scratch, re-install OSX up to 10.4.9 but . . . after the initial install from your Tiger disk . . download the COMBO UPDATER from Apple to bring you up to 10.4.9 DO NOT
allow Software Update to do the installing of OSX updates. Other Apple apps like iTunes, iMovie etc are fine with using Software Update.
Prepare for installation:
Boot from your original install DVD, run Disk Utility, (a) Repair permissions TWICE
. Validate your intended install partition.
Ensure that the OSX partition is at least 50gig if you are a heavy user; OSX needs swap files on your hard drive when memory runs low.
Quit all apps:
When you do a major OSX upgrade, quit all open apps while the installation is in progress, go for a walk around the block.
Copy the text shown below, open Terminal (It is in the Utilities folder in the Applications folder), drop the copied text into Terminals window; you'll be asked for a password, let it run. What are you doing? You are running the daily, weekly, monthly Cron (maintence) scripts which keep OSX tight and trim. It will take a minute of so to complete, watch Terminals window for the change. Note
: If you leave your G5 running overnight on a Friday the scripts will run automatically.
Copy the text below, open Terminal, drop the text into Terminal's window.
sudo periodic daily weekly monthly
Reboot holding down the SHIFT key; bootup will be longer as a series of repair and maintenance routines are run in the background and you will be asked for your password. After bootup is finished simply re-boot as normal.
Get Main Menu:
This marvellous free app http://www.santasw.com/
is the ultimate maintenance tool for OSX. All you really need to do is occasionally delete or clean your system caches which can run away from you from time to time. corrupt caches can also force recurring operation errors.
4. Bad Memory & PCI / USB cards
My G5 came with 4 "Hynix" brand memory DIMMS totallling 1 gig and I have proved to my satisfaction that at least two or all of the DIMMS are or became over time, incompatible with my G5.
Use JDEC standard memory.
and you will find that any memory sold as JDEC meets an international standard for quality. I have 4 gig of JDEC memory in my G5 at present and have never had a problem with it.
Clean the contacts with a soft eraser and re-seat your memory dimms:
(a) Nicotine and kitchen oils buildup on DIMM contacts, remove this residue with a soft eraser.
(b) Any memory in doubt should be placed in the outer slots. trusted JDEC standard memory should inhabit the inner slots.
(c) If you have high standard memory but have had kernel panics, remove and re-seat your memory DIMMS one pair at a time to elimate bad DIMMS and to ensure a good slot connection.
PCI USB cards:
(a) Re-seat your PCI cards - including your graphics card.
(b) There are quite a few USB 2.0 cards made for PC's that can be used in a G5; look for both 3.3v and
5v in the power specs. www.ratoc.com
has both 3 port and 4 port USB 2.0 cards that will work very well in any PCI user slot, my two have for two years.
5. Bad Hard Drives that do not show errors in Disk Utility:
I saved the best for last. My original 160gig SATA I hard drive that came with my G5 reported no errors in Disk Utility but I was getting random shutdowns after a fresh install. There is a guaranteed way to see if your drive has subtle errors . . . .
Apple Hardware Test:
This resides usually on Disk two of your original install DVD's. to get it going pop disk two into your dvd drive and reboot while holding down the OPTION key, this will bring up a pre-boot, volume selection screen - it will have a dark bluish background and will take a while to find what bootable volumes you have available. When it is done booting up, select Apple Hardware Test and run the medium test on your drives - it is not fast and could take an hour or more depending on your selection.
If you have a bad drive it will list it as either UPPER or LOWER as in the upper or lower drive bays in the case - I have forgotten which bay usually holds the boot drive . . . you can test for that by shutting down your G5 and seeing if it will boot after you disconnect one of two drives (if you have two).
Apple Hardware test found errors on my SATA I boot drive, I used Disk Warrior to repair the drive which I then put into an external USB 2.0 case to use for backups only. I replaced the offending drive with a 250gig Maxtor SATA II with 16mb of cache, it is noticably faster than the SATA I even though it is not working in true SATA II mode. In any case, I will be able to use this drive in my upcoming Mac Pro which does fully support SATA II.
Well, the above steps and the mainenance routines therein have kept my G5 clear of even the mildest hiccup for almost two years, absolutely no kernel panics nor random shutdowns.
If you are experiencing KP's and shutdowns often I would go straight to Step 5. to firstly eliminate this from your G5 rehabilitation program.
Suggested Maintenance Regimen
Spring & Summer : Blow out your case every 6 weeks.
Winter : Blow out your case every two months.
System caches : Delete or clean every three months.
Complete OSX re-install : Once every year - if you are not lazy
Strip down & remove PSU for de-dusting : Every two years.
NOTE : I do not "sleep" my G5. I have Energy Saver set to "Automatic".