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iMac G4 Kernel Panic

I recently set up a PPC iMac G4, 800 MHz. I pulled out the user-accessible 256 RAM that came with the machine and replaced it with this 512 stick from OWC. I had been using that stick in another machine for about a year without issue.

I erased the HD and did a clean install of 10.4 from a retail disc, and then did all the software updates to get it to 10.4.11.

Since setting it up it's been kernel panicking fairly often. I can't tell if there is a specific trigger for the kernel panic, but I was trying to get dropbox to work (supposedly it's supported for PPC) and it doesn't seem to like that very much.

Permissions and HD are fine, per Disk Utility/First Aid.

I can't run the Apple Hardware Test, because the optical drive on this machine doesn't work and AHT won't boot from an external optical.

I'd like to find out if there is an issue with the RAM. I've been running memtest in single user mode. When I run memtest with all the RAM in the computer, I get a FAILED message several times, and then a kernel panic. When I run memtest after pulling out the 512 RAM, I only get a kernel panic.

I tried to get a log from memtest, but it doesn't save--presumably because of the kernel panic.

Does anyone have experience with this? Should I assume it's the internal stick of RAM--in which case I would have to order a new one and take the machine apart to replace it, and then test it again? Or is there a better way to test the RAM? Any other components that could be causing the kernel panic?

Let me know if you need more information, and I'll try to take some photos of the screen during the test.

Thanks!

iMac, Mac OS X (10.4.11), PowerPC 800 MHz, 768 MG SDRAM

Posted on Mar 17, 2014 8:27 PM

19 replies

Apr 30, 2014 9:58 PM in response to K Shaffer

Thanks for the reply!

So in order to have a useful machine for the time being, I took both of the OWC RAM sticks (internal and external, total of 1GB) and put them in the 700 MHz iMac. It's working well now (slightly slower CPU than the other one, but at least it doesn't kernel panic). I ran memtest there and all the RAM passes--which I take to mean that the RAM is fine and the earlier memtest failures in the 800 MHz machine were caused by something else in that machine.

Is the clock battery the same thing as the PRAM battery? If so I've also replaced that in the 800 MHz machine with no effect, so I think I've ruled that out.

Which I guess leaves the logic board and hard drive. But is the logic board in use when the computer is being used in target disk mode? I'm thinking that not being able to zero out the drive with it in TDM indicates a hard drive problem--but I don't know if that could also result from a logic board failure.

Booting from an external in order to determine if the problem is in the hard drive seems like a good idea. I have this external with firewire - will that work?

I'll have to give some thought to buying a new hard drive if that is in fact the problem. Cost is a factor, and I really don't need two machines--I just need one that works. Then again, as long as I'm replacing it, maybe going with an SSD would be a good idea.

I'll go through those guides and your comments about the teardown more carefully next week, and I suspect I'll have more questions about it. In the meantime, I need to get some thermal paste. What kind should I get--ceramic or silver?

Thanks for the help!

K Shaffer

Level 7

34,984 points

May 1, 2014 12:58 AM in response to andbeonetraveler

The hard drive indicated in your link above won't work to boot a PowerPC

Mac computer, and the external should have a power supply so it won't rely

on the computer (should be running before computer is started up.) To get

and use a FireWire external enclosure if you want to have a bootable system

clone on an external drive, that can't be a USB ported enclosure.

And it can't be running off USB/FW port power. FW400 is suited for use with

many pre-2006 PPC Macs, and enclosures with oxford-type chipsets work.

The model listed below is in a durable case, has its own power supply, has

the oxford chipset, and can run a computer from a cloned OS X. (And it also

has USB2.0 ports, but they won't boot a PPC Mac; OK for storage access.)

The others likely will not. Here is an example of enclosure set to go w/HDD:

http://eshop.macsales.com/item/OWC/MAU4S7500G16/

Similar examples with & w/o HD drives (ports FW/USB) installed:

http://eshop.macsales.com/search/Elite+Pro+Oxford+934

The silver thermal paste such as OWC has seems to work on both desktop

and portable computers adequately, it is better than they'd used when new.

You may be able to get a download of vintage Carbon Copy Cloner

for use in OS X 10.4 or 10.3 systems, so as to copy/clone the system

off your computer if you wanted to keep it (not erase/reinstall) for use

in another replacement hard disk drive. Check the sites for CCC at

bombich.com, or SuperDuper at shirtpocket site, for older versions.

These run free, so are handy to have; especially if you have a boot

clone and wish to re-install the entire thing into a computer. Most

other utilities run from OSX clone on external self-powered FW HDD.

The 3.6v 1/2AA Lithium battery used in various Apple desktop models

can be called a PRAM battery, as it powers a chip that keeps settings

correct until it goes dead, and it does not get re-charged by the Mac.

It also powers the system clock that keeps the system + all files in order.

OWC has these for about $4. or so. You can always pay too much. I used

to buy these in bulk, for about 50¢ each, when restoring older PowerMacs.

Be sure to read up on the issues of using an SSD, since these desktop Macs

take the 3.5" larger size and for the cost, a 7200RPM 500GB HDD is less.

The SSD may do OK if in an external enclosure, with FireWire. If you hope to

swap a HDD from an enclosure into the old ATA/IDE (PATA) Mac computer,

then you have to be sure to get an SSD that works in the PATA computer.

And also get an external enclosure that works with the SSD, or other HDD.

Some brands of SSD may include or provide an adapter for PATA & SATA.

Don't bet on it, ask if you contact a product specialist at the retailer.

I'd not overly complicate this. And to have/get an externally enclosed HDD

for backup and bootable system clone/copies of your Mac's OS X, can be

a different enclosure than you'd use if you get an SSD. I'd partition a larger

capacity 7200RPM 3.5" and use that for more than one purpose, backup in

one partition and perhaps room for the cloned OS X boot system on another.

The OWC site has two case sizes of SSD, the 2.5" Legacy for portables, &

the 3.5" Legacy for desktop models. An external enclosure should match;

given the other aspect is PATA vs SATA. A hard drive that will live in the

external enclosure, would be OK if both parts inside there were SATA.

Just you would not be able to swap SATA HD in there with w/ ATA iMac.

The iMac uses the standard 3.5" ATA/IDE, and 7200RPM may be faster

than stock in an early 700/800MHz iMac. Seems to me they shipped w/

5400 RPM spin-rate, when new; so they may run warmer with faster HD.

Anyway, these are considerations and possible trade-offs; an SSD for use

inside an early iMac G4 model may be OK, but there are other aspects of

those which may be impractical to upgrade too much. The OS X limit in

the slower processor is Tiger 10.4.11. Or, you could run a custom linux or

unix based system. A few/free are out there, but they won't run Apple s/w.

Be sure to check out various options before you finalize a plan... 🙂

May 8, 2016 9:08 PM in response to K Shaffer

I put this project aside for a while and just got back around to it. Source of the kernel panic is officially the logic board (or a logic board connector).

I took apart the 800 MHz and installed the hard drive from the 700 MHz (using both the links provided by K above and the iFixit guide mentioned previously). With only the hard drive that was in the 800 MHz installed, it couldn't find a startup disk. While I was doing the hard drive swap, I noticed that one of the pins of the connector attached to the logic board (the one that plugs directly into the connector attached to the snowball, that you have line up when reattaching the base--not one of the connectors with wires going into it) was bent and smashed all the way down. The computer was a hand-me-down, so it had probably been opened up at least once previously. I straightened the pin as best I could, but after installing the functional hard drive, the computer started up but kernel panicked within a few minutes.

So I stripped some parts from the 800 MHz and I'm going to get rid of it and use the 700 MHz. Neither of the optical drives works, so I took them out. I tried plugging in the bad hard drive into the optical drive slot of the 700 MHz, with the good hard drive plugged in to the hard drive spot. But the computer couldn't find a startup disk when I did that. Not sure if that's because it gets confused by a hard drive in the optical slot, or because that hard drive was bad.

Might be nice to get a cheap hard drive and add it in there for extra space, though. Does anyone know if a second hard drive can be added to the optical drive slot of this machine?

K Shaffer

Level 7

34,984 points

May 9, 2016 1:14 AM in response to andbeonetraveler

A situation with the identity of the hard disk drive, and the optical drive, as seen

by the logic circuitry in the iMac, may yield unhappy results when trying to swap

one kind of drive with another. The data transfer speeds of optical drive could be

lower than those of a hard disk drive, depending on the configuration.

The computer may see the optical drive as a master, but this is an ATA IDE (PATA)

or Parallel ATA setup; and not one using SATA or serial ATA. The optical drive is

usually set to be able to start the computer with the system DVD or CD.

Anyway, the hour here is late and my memory on this topic isn't helpful. I'd have

to re-search information such as everymac and some from mactracker, among

others to see what I may be missing.

However, you could see about using a FireWire externally enclosed hard drive

for the system as a FW400 should be fast enough for booting an OS X. Another

idea would be to get and ready an OWC Legacy SSD (for ATA/IDE) from mac

sales.com and ready it for use before installing it. These are in use for several

models of older non-SATA and can be an impressive improvement over anything

stock when booting the OS or using any applications. Enough to supplement the

lack of additional RAM since swap files and virtual memory effects are good.

Later iMac G4 models had 7200-RPM 3.5-inch ATA/IDE drives that may be hard

to replace nowadays; earlier 700/800MHz had 5400-RPM 3.5-inch hard drives.

So this alone could effect better performance; while the Legacy OWC SSD for

older portable and desktop computers (the unit is 2.5-inch, and thinner) is best.

The cost & effort to change the drive over to an SSD along with troubleshooting

the setup, should issue develop, could be a deal breaker for such a Mac model.

An SSD should run cooler in iMac G4 series. There are several standard parts

in these that tend to be unstable over time; so spares may be difficult to locate.

For a time, MCE brand offered replacement optical drives; OWC may have some.

They had one in stock for awhile; other models for slot-load are more common.

I'd try to keep the internal optical drive; unless you could locate and figure out how

to use to your advantage, an externally enclosed tray-loading FireWire superdrive

equivalent. This kind of FireWire drive has a controller chip (as does external drive

housing) that allows for Mac OS and OS X booting. Old chips were 'oxford-type'

and newer ones are different, macsales.com offers some enclosures to boot from

that would be used with Clones or technical troubleshooting, and so on.

Though I've probably missed your question in this reply, I've just stopped in late to

see what kind of ASC activity is going on. Local time is few minute after midnight.

I have a iMac G4 1.25GHz 17-inch model USB2.0 that kernel panics, it was included

with one that was working at the time, as parts. I also got the original box. A working

one of that transaction has needed superdrive replaced. Those used a Panasonic

version with special firmware; there were topics in some sites years ago about how to

try & flash the firmware to get a different model to work. The optical drives appeared

to fail, about when you'd upgrade the OS X. No firmware upgrades solved the issue.

Anyway, it's time to go offline...

Good luck in this matter! 🙂

iMac G4 Kernel Panic