Erratic Trackpad behavior (#3): 2005 PowerBook G4 model problems

We continue to cover erratic trackpad behavior from various Apple portables -- particularly 2005 PowerBook G4 models with the first new trackpads not manufactured by Synaptics.

Taps not recognized In addition to a previously covered issue where trackpad button clicks are not recognized, MacFixIt reader Terry Dorn reports an issue where taps on the trackpad -- when configured to act as mouse clicks -- do not work reliably:

Dorn writes:

"Purchased a new PowerBook G4 15" (2005) from local retailer about two weeks ago, and this past weekend began to notice erratic behavior from the trackpad. Namely, taps (single or double) not always recognized, and sometimes it won't come out of sleep mode by simply tapping on the trackpad. Otherwise, I love it. Looks like a trip back to the store, which is an authorized Apple reseller and thankfully they have a good repair department."

Jumpy, inconsistent behavior We continue to receive reports of jumpy cursor behavior and other strange behavior from trackpads on 2005 PowerBook G4s.

MacFixIt reader Ben Markens notes that drag processes can be cut short abruptly "I have noticed erratic behavior with my new 15" 1.67 GHz G4. Click and drag seems to drop prematurely on a regular basis. No problem when using a mouse."

Alan D adds "The touchpad button on my new 15" PB is very stiff and awkward to use. Many lost drags and missed clicks."

Chris notes an apparent new tracking speed scheme that allows quicker movement horizontally than vertically:

"I've noted some differences with the trackpad on my 2005 PowerBook G4 15". For me, it appears to be a little more complicated than just being slow -- it seems to depend upon which direction I'm dragging.

"From left to right, things are pretty normal, but from top to bottom, tracking speed seems to be roughly half. I can kind of see what they're going for...the screen is wider than it is tall, so you don't need as much acceleration top to bottom. However, this can be very confusing when moving from a previous machine with a trackpad that doesn't work this way, particularly when going diagonally. I find I have to constantly reposition my finger, compared to my 12" 1GHz machine where trackpad use is basically transparent for me at this point. If this is indeed a new feature, I hope they eventually include an axis ratio option in future software revisions."

Triggered by Mac OS X 10.3.8 Meanwhile, users continue to report erratic PowerBook trackpad behavior after installing Mac OS X 10.3.8.

For some users resetting PRAM this has restored normal operation in both this case, and the aforementioned non-functional F12 key problem. Resetting PRAM is accomplished by holding down the Option, Command, P and R keys at system startup until the computer restarts again and you hear the startup sound for the second time.

For others, however, the problem persists.

Chris Larkin writes:

"Every since I did the 10.3.8 update, my trackpad and keyboard stops responding randomly on my 1Ghz PowerBook 15in Ti (SuperDrive) w/ 1Gh RAM. USB keyboards and Mouses will work fine if I plug them in. A quick work around for me is to force the laptop to sleep by closing the screen and wake it back up. I've reset the PRAM and PMU and did a repair permissions and the issue still is there."

Frank C. adds:

"I've been experiencing erratic trackpad behavior ever since I upgraded to 10.3.8. The pointer will all of a sudden stop and then jump around the screen. Sometimes it will fly across the screen with the slightest touch. It will also move slow and then all of a sudden rapidly speed up.

"It also fails to recognize clicks on the trackpad button that occur on about 20% of the attempted clicks."

Feedback? Late-breakers@macfixit.com.

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