Adventures with an Overheating PowerBook, the 10.5.6 Update, and Other Things

I downloaded the Mac OS X 10.5.6 update the day after it was released, which for me involves a 24 mile round trip to the library, whose WiFi connection is slow - but still a lot faster than the 26,400 bps dialup connection I get at home. Anyway, once I had it in hand, I continued to hold off running the installer, my hesitation due to an extraordinarily large volume of post-upgrade trouble reports I'd been reading on various forums.

Hot Running

However, on New Year's Eve, my usually dependable, predictable, solid-as-a-rock trouble-free 1.33 GHz PowerBook G4 started running hot, with its cooling fans cutting in and out on what settled into a roughly 3-minutes-on, 30-seconds-off cycle. I've found that the PowerBook does tend to run a bit hotter after a fair bit of time elapses since the last system reboot, and certain web pages can also have content that seems to stress the processor. In the latter instance, closing the page, the browser window, or quitting and restarting the browser usually restores cooler running, as does rebooting the computer.

This time, however, none of the usual nostrums worked, and I found that the freshly rebooted system was still cycling between processor temperatures of 58.5°C (the cooling fan cut-in threshold) and 55°C (the temperature where the fan goes silent again). This machine normally runs in the high 40°s and low 50°s under light to moderate processor loads, with the fans mercifully silent.

Something had obviously changed.

I decided to run the OnyX Repair Permissions, cron scripts, and cache dump system maintenance routines and rebooted hopefully, but no joy. The fans began howling almost before the boot cycle had completed.

It's the OS

For purposes of diagnostic comparison, I next tried booting into OS X 10.4.11, which I keep installed on another hard drive partition, and the temperature readout stabilized at 49° to 50° - well below the fan activity threshold.

It seemed this was not a hardware problem.

Back in OS X 10.5.5, I was still getting overheating. I figured I might as well try updating to 10.5.6, not a project was really enthusiastic about starting at 1:00 a.m., which it was at the time. But I've always had pretty good luck with Mac OS X updates, there was the fresh system maintenance, and I wanted to fix the problem, so I resolved to go ahead.

Update Problems

The update installation ran normally, taking about 15 minutes and delivering the welcome "The Software Has Been Successfully Installed" message, but that was where the usual routine petered out. On the obligatory restart, I got a gray screen for about half an hour, accompanied by a lot of hard disk activity interspersed with periods of silence that left me wondering if the machine had hung. Finally, a blue screen appeared, followed by a second reboot and the gray screen again.

I finally lost patience and hit Cmd-Ctrl-power, forcing the computer to reboot, then holding down the Shift key to select Safe Boot Mode. Anther long wait, and my finger holding down the key was tired by the time the PowerBook did boot at last. The Desktop reappeared, but it was again accompanied by the caterwauling fans.

At that point I tried one more reboot, a normal one this time, and mirabile dictu, the machine settled down to running at 47° to 48° and stayed in that range while I sent a few emails and battened things down for the night, it by that time being 3:30 a.m. I went to bed optimistic that problem had been licked.

Not.

About midday on January 2nd, we had a short power outage while utility crews cleared some fallen trees off a neighbor's power lines, residue from a major snow and wind storm that battered us for about 30 hours on New Year's Day. The power going out and coming back on usually makes the sleeping PowerBook wake up, and so it did this time, only I was out and didn't notice it until several hours later, when I walked into my office and found the machine running with the fans screaming away - nothing changed and the same two or three programs open as I had left it the night before. Most disappointing.

Maybe It's Not the OS

I keep a cloned copy of my hard drive and boot system on an external FireWire drive, so I booted up from that system (OS X 10.5.5). I was delighted to observe that the PowerBook settled down running at 47° to 50° under light to medium processor loads, holding that temperature range through a several hour work session. It was even a bit more lively than usual, since the external drive is a 7200 RPM unit as opposed to the 80 GB 4200 RPM drive in the laptop.

However, there was still something evidently amiss with the Leopard install on the internal hard drive, and I determined that I was probably going to have to do a clean system install in order to eliminate whatever was causing the overheating, something it hadn't had since I purchased the computer just shy of three years ago, beginning with OS X 10.4.7 or so and just updating and upgrading that original installation through every version since.

I run dozens of applications, probably more than 100 over the course of a year, many of them beta or even alpha builds, so the possibility of some sort of corruption was not implausible. In the meantime, the external FireWire drive was doing a fine job as a stand-in, underscoring once again how wrongheaded it was of Apple to drop FireWire support from the new Unibody MacBook.

On Saturday evening, I tackled the system reinstall. I dragged all the System related files from my hard drive's main boot partition to the Trash and flushed, which took quite a while, as there were well over 200,000 (mostly small) files to dispense with.

Backup Serenity

With a recently cloned system on one external hard drive and an up-to-date Time Machine backup on another, I had no anxiety about trashing the old system.

At that point I thought it might be a good idea to defragment the data still left on the boot volume (mostly applications and data archives), so I started up Drive Genius 2 and commenced a defrag run, which crapped out with the process about half complete. A message appeared saying a directory problem or somesuch was preventing the defragmentation from completing and suggesting I run the Drive Genius Repair module. That I did, and it returned an "appears to be OK" clean bill of health.

Back to the defrag module - but the process stalled again.

All right, perhaps it was time for DiskWarrior. I popped in the DiskWarrior 4 CD and booted from it, something I don't do as often as I would like, since the bootup takes 10 to 15 minutes - longer than the directory rebuild process itself, which in this instance ran smoothly. DiskWarrior did find some damaged directory files, as it usually does, but nothing major, and it was able to repair them when it replaced the directory with a fresh new one. While I had DW up and running, I took the opportunity to rebuild the disk directories on the PowerBook's other two partitions as well.

A reboot, and back into Drive Genius 2, only to discover that the program not could not mount that partition at all.

Reinstall Leopard

I decided to give up on the defrag and just go ahead with installing OS X 10.5 from scratch, opting for an almost-but-not-quite clean install, deciding to save myself a lot of configuration tedium and ennui by importing the User and settings files from the cloned system on the external FireWire drive, which seemed quite healthy.

The installer on the Leopard DVD did its stuff without drama, after which I ran the 10.5.5 Combo updater. Experimenting a bit after the reboots, I found that the heat issue was somewhat improved, but the PowerBook was still running hotter than it had customarily done in the past.

Might as well go for it and run the OS 10.5.6 updater - and this time it worked a lot more quickly and smoothly than on my first adventure described above. It booted with reasonable dispatch with no gray or blue screen stalls.

At the end of several days and a couple of very late nights, I'm happy to tentatively and cautiously report success at last. As I put the finishing touches on this column, the PowerBook running OS X 10.5.6 from its own hard drive is six hours and 40 minutes into a work session, and the cooling fan has only cut in once in that time during a flurry of email and page loading throughput via the internal dialup modem, which does tend to make the machine run hotter when in use.

However, for the most part the Temperature Monitor readout has been ranging from a low of 43.5° to 52° - well short of the 58.5° fan cut-in point, and 10.5.6 has been a smooth performer so far.

Hoping it stays that way.