Is keyboard problem logic board

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PowerBook G4 Aluminum 17" 1.67 GHz (High-Res)

Model A1139 / 1680x1050 screen resolution

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paige @paige62385

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Posted: Jun 14, 2010

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Is keyboard problem logic board

Is my problem keyboard, upper case (trackpad/kb logic board), or main logic board?

Started after I replaced hard drive. Keyboard begin to “stutter” - did not register characters when pressed; extreme delay when pressed; registered multiple (usually 2) characters when pressed. Has gotten worse. Over time I’ve noticed:

1. After a sleep, restart, or off/on; it works fine for a while - used to be 30 minutes, now about 5.

2. problems usually first noticeable with Commnd-key or Shift-key strokes (any double key), then gets worse to any key, backspace /delete;

3. on 2 occasions lost cursor/trackpad control & had to restart.

4. on 2 occasions got the kernel message ... white writing on black text dropping down on left side of screen basically saying kernel ?failure/panic/???( dont’ recall exactly) but system was frozen and had to restart.

Does this kernel panic or whatever automatically mean “motherboard?”

What about “upper case” which includes the trackpad logic board?

Actions taken:

Reseated all cables in clips:

Keyboard to upper case logic board.

Upper case logic board to motherboard cable

Trackpad to upper case logic board

Replaced entire keyboard with a tested one from ifixit, which included a new keyboard to upper case logic board cable and new backlight cable; and reseating all of the above yet again.

Help appreciated.

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1 Answer

paintbyletters @paintbyletters Rep: 121 3 · Answer 1 · 2010-06-14T17:39:21-07:00

I don't know what your level of expertise is, so forgive me if this gets simplistic.

Were any of these problems showing up before you changed the hard drive? If not, then the answer is probably with the keyboard - either it is defective or not properly seated.

Have you tried using an external keyboard?

Also, check the keyboard socket on the logic board for any evidence of breakage, scorching, corrosion or verdigris that is often left behind by liquid damage. If there's damage, then, yes, you've got a logic board problem. :-(

Light corrosion maybe removable with a soft bristled toothbrush.

When does the kernal panic occur? If consistently on start up, then you may have to simply format and reinstall the OS on your hard drive. Also, make sure that you are using an OS that your Mac can handle.

Bad RAM or badly seated RAM can cause kernal panic. Try reseating the RAM, or removing one stick of RAM, or using known good RAM, and see if the problem is resolved.

It can be tedious, I know, but if all of the above fails, try removing internal devices from the logic board - one at a time, and see if the problem persists. Disconnect the airport card, bluetooth, the optical drive, the keyboard, etc.

If you remove the keyboard, you will have to start the laptop by shorting the power-on pads that are on the logic board. They can be a bugger to find and are not in the same place from model to model. Just look for two tiny pads with the letters PWR. Use a flat blade screwdriver to make the connection between the two.

Hope some of this helps!