PowerBook G4: premature shutoff follow-up; DVD drive noise

We received several replies confirming our item Saturday about G4 PowerBooks shutting off. We do not have a clear picture of how many units may be affected. It does appear that the PowerBook case flexing causes at least some of the problems, although there may additional triggers. It should also be noted that Apple recommends never moving a laptop when it is turned on. However, several messages, including one below, report that the machine has also shut off when asleep. Here are the highlights:

Terrell Smith writes: "If the computer is moved (like holding it on a lap, in your hands, or even moving it on a desk) the case seems to flex a bit, causing the computer to suddenly go totally dead. This requires a reboot, plus the date & time settings revert to 1904. I have removed and reinstalled the battery several times to make sure the contacts are clean but it doesn't help."

Daniel Shockley writes: "I got my G4 PB 3 days ago, and it has shut off twice. Once, when I was holding it on my lap, and another time while it was in a carrying case, asleep. I've met one other person who had a G4 PB, and the same thing has happened to him twice. One time while it was sitting alone on a desk using only battery power while an installation was running."

Michael Edwards writes: "I also experienced inadvertent shutdowns of my PowerBook G4 when I held the unit with my left hand over the battery. I could easily reproduce it. An Apple senior tech told me that the flex in the case can cause the battery to become momentarily "disconnected" from the terminal and the result is almost like a short circuit. Apple sent me a new 500 MHz G4 overnight, saying their engineers wanted this unit for inspection."

Christopher Thompson adds: "I've experienced the same problem, though not on the same side of the case as the battery. If I use my right hand to grab the right side of the machine, where the DVD-ROM is, the computer shuts off and the date and time must be reset. I suspect it is possible that putting pressure on that side of the machine causes the battery to lose contact."

Gabriel Biskup and others have observed that after the unexpected shutoffs it appears as if the Parameter RAM was reset (e.g., date and time are changed to default setting).

Terrell Smith also noted: "If my computer is slightly tipped so the unit is not quite level, either on a table or resting on my lap, the spinning CD/DVD disk can sound like a buzz saw. I suspect the spinning disk comes in contact with the case. It doesn't always happen. Again, the above mentioned case flex seems to be part of the problem." Gary Adams encountered the same noise on an iBook SE. He writes: "Flexing of the case or pressure above the drive area produces the most-horrendous sound I've ever heard from a Mac."