Keyboard Problems Again

My laptop keyboard's been out most of the past month. It was never right after it got doused in water, even though I replaced. There's a fuzz connector under the T, G, and Y keys that connects the keyboard to the motherboard. Ever since I replaced the keyboard, I've occasionally had to press down on those three keys very firmly in order to regain keyboard and trackpad. Well, one day last month that trick stopped working. (Luckily I have an external USB keyboard and mouse so I can keep working.)

The ambient light sensor for the backlit keyboard always works, so there's power to the keyboard. However, none of the keys work (not even the CAPS LOCK light).

This failure is different, though. I have keyboard right after the laptop boots, but after a while, it goes out (and no amount of pressing on TGY brings it back). For instance, one time I lost keyboard in the middle of typing 11 minutes after a reboot (I was on AC). The next time I was on battery, and it took two hours to go out. That would indicate a heat problem, and fuzz connectors aren't the most solid connection under the best circumstances. However, I think it's load-related (keyboard goes away when I see the CPU head up) more than power-related. So still a heat issue, but more about CPU than AC versus battery.

However, I collected a list of suggestions from the Internet on what to try for PowerBook G4 keyboard problems.

1. Disk Utility's Repair Permissions
2. Zap RPAM by pressing COMMAND-OPTION-P-R immediately after the startup chime. (This was tough, until I let the laptop cool off for a couple hours so that the internal keyboard worked because the external keyboard isn't loaded in time.) I also tried the Open Firmware zap by pressing COMMAND-OPTION-O-F immediately after the startup chime and then running these commands: reset-NVRAM, set-defaults, and reset-all which made it reboot normally.
3. Reset PMU by pressing and holding the power button for 5 seconds when the laptop has no AC and no battery.
4. Try safe boot by pressing the SHIFT key after the startup chime.
5. sudo rm ~/Library/Preferences/com.apple.BezelServices.plist /Library/Preferences/com.apple.BezelServices.plist
6. Reapply last combo update.

Yes, these are predominantly software fixes for what appears to be a hardware problem, but it doesn't cost anything to try. It does make the new MacBook Air very tempting, but I don't want onboard Intel graphics.

1. Update 1/19/2008: Repair Permissions didn't fix the keyboard.
2. Update 1/21/2008: Neither form of zapping the PRAM fixed it.
3. Update 1/27/2008: No luck resetting the PMU. Twice.
4. Update 1/29/2008: Safe boot didn't fix it.
5. Update 1/31/2008: Removing BezelServices didn't change anything keyboard.
6. Update 2/12/2008: Combo updater was not the ticket either.

So it looked like a hardware problem, and sure enough, I think this proves it. The fuzz connector between keyboard and motherboard can only be reset so few times, and I went over the limit. This laptop will just have to stay docked ...