I have a 667/DVI powerbook, with the frustrating behavior that it goes to sleep instantly if there's *any* pressure on the left palmrest or left option/command buttons- the area above the battery contacts. I'm basically convinced it's a matter of the case flexing the wrong way and shorting something out that makes it sleep instantly.
I've tried running it with another battery, and no battery, and it keeps the same behavior. Are there any known fixes for this scenario?