[Michael Ash]

I've been experiencing random freezes and kernel panics for about a week and a half now, and I've run out of things to reset or remove. I'd appreciate any advice anyone may have.

First, the symptoms. Starting about a week and a half ago, the machine would freeze at random, on average every three or four hours. This isn't exact; sometimes it would go the whole day without freezing, sometimes it would freeze, then freeze again as soon as it was done rebooting. Normally this happened in Panther, most frequently right after booting or waking the computer from sleep, but it could happen at any time. During the course of my troubleshooting, I booted into OS 9 which also froze a couple of times at random. More bizarre, the boot chooser you get when you hold down option while booting froze twice. Another symptom is an occasional failure for the screen to turn on when booting. It stays completely black, even though the computer boots and seems responsive (hitting the volume keys gets me beeps, hitting the power button and then return, R, or S lets me reboot). Rebooting, and even a hard shutdown won't solve that one; lots of mucking around with resetting PRAM does. And one more symptom; a graphics glitch showed up exactly once, in OS X. I wasn't doing anything in particular, and suddenly a small rectangle appeared near the upper-left corner, filled with garbage.

This is on a PowerBook G4/400 running OS X 10.3, 10.3.2, and occasionally 10.2.6 and 9.2.1. The freezes haven't shown up in Jaguar, but I have barely run Jaguar so I can't say. I have 640MB of memory, of which 512MB is a third-party addon. I have an airport card which wasn't original with the computer. The rest of the hardware is original.

The machine was dropped (more properly, "I dropped the machine") once, with no apparent ill effect at the time other than some cracks in the plastic border around the keyboard/trackpad area. This happened about a year and a half ago. The cracks have slowly widened until they went completely through the border in two areas. One crack is at the lower left corner, which is not coincidentally where it hit the floor. The other crack is in the upper left corner, about an inch down from the actual corner, in the plastic around the vent. It's this one that worries me. It eventually broke all the way through, and it flexes a bit when I move the screen around. After the crashes started happening, I glued it back down in case it was moving something inside, but this didn't help. Of course, the flexing could have caused permanent damage to internal components.

I've done a good amount of troubleshooting. My first suspect was hard drive corruption. This was confirmed when I found some errors on the drive, but I fixed all of them with multiple drive recovery apps, and eventually reinstalled OS X, with no help to the problem. (Actually, it took my machine from being totally unusable to merely nearly unusable, so I suppose that could be 'help'.) In the course of all of this, I reset my PRAM and hit the reset button on the back of the computer several times. I ran Apple's Hardware Test CD several times as well, with every test passed. I finally started to think that it's a memory problem, as my 512MB module died a while ago. I got it replaced in May, and so I thought maybe the replacement is dying now. But the problem is really hard to reproduce since it's so random. I took out the 128MB module and the system crashed after only a few minutes. I took out the 512MB module and the system stayed up. I thought that was it, then my system just froze at random again this evening. I'm not sure if it was a one-time thing or not, time will tell.

I think that covers everything. My questions are several. First, is there anything I'm missing? Some potential cause I haven't thought of? Second, is there any resetting that I haven't done? Last, if it is some deeper hardware problem, what are my repair options? Should I even try, or would I be best served by simply giving up and buying a new computer? If I do repair it, where? There are no Apple dealers in my city, but there are a few chain stores that happen to sell Apple computers. Would I be better off trying with one of the stores or with Apple directly? In case it's relevant, I bought the computer in the US but I'm now living in France.

Thanks a lot for any responses.

[Michael Ash]

Well, nobody has responded to this message, so I'm replying to myself just in case anybody is interested in how it was fixed. I think it's fixed. It's been about a day since it last froze, which is longer than it's ever gone before, so I think it's ok.

And so what was the problem? Drumroll.... the mouse!

I have an Apple optical mouse, the model that is notorious for having a broken cord after a while. Mine is two and a half years old. Apparently the cord can be broken in such a way that it mostly works, but occasionally loses contact, and I guess this can actually manage to crash the computer. I never would have guessed the problem except my father had the exact same problem and figured out the solution not one week ago.

So if you're having random freezes and you have an older Apple optical mouse, unplug it!

[dekkoman]

Michael,

Thanks so much for your post - I think it's the answer to my prayers! I have a g4 that, for the past 2 years, has been going "beep beep" and then freezing (while continuing to beep). I would shut it down, and leave it for a while (sometimes overnight) and it would seem to reset itself. Finally, a few weeks ago, it wouldn't start up at all. I rescued all the files off it, and did a clean install of Tiger. It seemed good for a week or so and then, "beep beep"! I read your post and had another mouse laying around, so plugged it in. And voila! - it started right up.

So again, thanks so much for answering your own post - alot of people wouldn't have.

BTW, even the Apple Care 'specialists' couldn't fix this one when I called about it.

Tim Webster
Sydney

[Michael Ash]

Wow, what a surprise to get an e-mail notifying me of a post to a year-old thread.

I didn't follow up as much as I should have. I probably forgot about this post in the continuing saga that was my broken powerbook. The problem was so difficult to reproduce that I found quite a number of different "solutions" to the problem, just by coincidence that the problem would go away for a while after I changed something.

Ultimately, the problem was a broken motherboard. I had dropped the computer a year and a half before the problem began, which slightly cracked the case near the hinge with the screen:



When the crack finally went all the way through the plastic, opening the screen started to bend the motherboard. A few months later, something on the motherboard broke slightly, and I started to get these weird intermittent problems. I verified this by taking the computer apart, running with the case open, and verifying that I could reproduce the kernel panics with 100% reliability by simply pressing gently on a certain spot on the motherboard, which happened to be the spot that was being stressed by this crack.

I hope the mouse is the solution to your problem, even if it wasn't ultimately the solution to mine.

[kick52]

i wonder if my mouse is anything to do with my panther crashes? ill have to try with a different mouse......

[adamgarrigus]

I just brought home a used G4/533 to replace a G3 Bl&W and have been getting the "beep beep" thing. It seems as though the more "beep beep"'s, the less responsive the system becomes. Repaired disk & permissions. Have to try the HW test & the mouse (!).
...-~===~-...
Mac G4/533 | 512Mb | Mac OS X 10.3.9

[billychamp]

G4 733 (DA)
I have been having the same problem for quite a while. After it happens the computer will rarley boot again without messing around. I am pretty sure it is not the mouse as it has not fixed it to boot with nothing attached but power. I don't think the motherboard has been physically damaged either. Had thought that it was a power supply problem but I am not sure why I thought that. If I blow clean the whole inside of the computer it sometimes fixes it for a few days. But it has also "fixed itself" if I just leave it for a few days. I am going to try reconfiguring the ram after reading above posts. Will update.

[midnightken]

I also have experienced the same symptoms for several years on a G4 machine. First running 10.1.4, then upgraded to Tiger, 10.4.3, thinking that would fix the problem but still have freezes with "beep beep". It only happens when the computer has been idle, especially logged off, or asleep. The only solution is powering down, waiting for 30 seconds and powering up. Soft reboot doesn't work and a hard reboot without the waiting period doesn't work either. I read somewhere that the 2 beep signal means a bad RAM or PRAM. I tried reseating the card but to no effect.