Two weeks ago, while I was in Boston, I was at my laptop when suddenly the backlight turned off, my CD drive tried to eject a non-existent disk and it locked up. I rebooted it, and everything was normal, except that my trackpad no longer worked. In fact, my Mac couldn't even see that I had a trackpad. This is not a big deal, as I do have a few external mice, but it is annoying. A week ago, I decided to see if disconnecting and reconnecting the trackpad cable might fix the problem. So I popped the bottom off my PowerBook, and I saw Figure 1 below. Note that the plastic tape on the trackpad cable has a gaping, melted hole in it.
Figure 1: PowerBook Trackpad Cable with Big Melted Hole
Flipping that tape back reveals Figure 2, below. Note that there is are two capacitors, and a pile of black ash where the third one should be. The burnt capacitor itself has actually become disconnected from the circuit board, since the heat melted the solder.
Figure 2: PowerBook Motherboard with Fried Capacitor
Frankly, after seeing the damage, I am amazed that my PowerBook continues to work at all! In a strange coincidence, shortly after this happened I read a second hand comment from an Apple hardware engineering that apparently they put it extra capacitors to try and avoid this kind of failure. I guess that the capacitor that went on my computer was a critical one. Unfortunately, travelling without a trackpad is very inconvenient, so I may be forced to replace this thing soon. One of those new MacBook Pros might be pretty sweet.