I was having some trouble with my Duo.
Now, this was no ordinary trouble. This wasn't some problem with somebody's machine crashing now and then, or constant unjustified out of memory errors, or anything trivial like that. No, this was a problem with my machine, and hence it was a matter of critical, nay, near national, importance.
The problem manifested itself in two ways. The most common was when the machine was undocked, running on battery power. It would start to boot up happily, and then suddenly shut down in a manner best described, as Dave Barry would put it, as "suddenly and without warning." This usually happened during boot, but sometimes it happened a minute or two after the Finder appeared, and occasionally it happened any old time at all. If it hadn't been a complete shut down, I would have attributed it to computer narcolepsy.
The second manifestation seemed to be modem-related, and led me to believe that it was a separate problem altogether. Whether on battery, power adaptor, or dock power, the whole machine would shut down the instant the Express Modem connected. This problem was not nearly so common, which was good, because otherwise I would have been prone to screaming fits long before now.
I started by calling around for service and learned, to my dismay, that the minimum wait in this town (we're talking Seattle here, not some burg where they're still impressed by digital watches) for any kind of service is a week. I have no proof, but I strongly suspect that I would shrivel up and turn to dust if I was without my machine for a week. So I asked on the net rather than calling Apple and figuring out how to send my PowerBook into the wilds of Texas, or wherever Apple fixes things these days. Seattle PowerBooks don't like dry weather anyway.
Alarmingly, quite a few people responded, but mostly with requests for a solution. It appears that I had a common problem. Most of the responses came from Duo owners, but a couple came from owners of other model PowerBooks. Luckily, two responses held a simple answer.
If you slide the battery out of a Duo and look inside (the Duo, not the battery), you'll see the contacts way in the back. They are partially supported by a small piece of foam which presses them firmly against the battery terminals. In some cases, this foam doesn't do its job very well and you get poor, sporadic contact with the battery - the PowerBook disapproves of such treatment and responds by shutting off.
So I reached in with a dry, clean, non-metallic object (a Pilot BP-S medium ballpoint, back end first) and carefully bent the contacts toward the battery terminals. It took about five minutes, and I haven't had either problem in nearly two weeks since - so apparently the Express Modem was also sensitive to the battery problem.
This may void your warranty if the Apple Thought Police ever find out, but it beats shrivelling up and turning to dust.