Quality issues

Some owners have experienced failure of the lower memory slot, with the typical repair being the replacement of the logic board. Apple had started a Repair Extension Program concerning the issue,[3] but it has been noted that some models displaying the issue have not been included. This leaves certain PowerBook G4 owners with only a maximum of 1 GB of RAM to use instead of a full 2 GB, unless they wish to purchase a 2 GB stick to put in the working slot.

Apple previously had a Repair Extension Program to fix the "white spot" issue on its 15" PowerBook displays.[4]

There has also been a rash of reports concerning sudden and pervasive sleeping of 1.5 and 1.67GHz models known as Narcoleptic Aluminum Powerbook Syndrome.[5][6] Symptoms include the PowerBook suddenly entering sleep mode, no matter what the battery level is or if it is plugged in. One cause is the ambient light sensing, and associated instruction set coding, with possible keyboard backlight and sleep light issues accompanying the so-called "narcolepsy". Another cause is the trackpad heat sensor monitoring the trackpad; system logs report "Power Management received emergency overtemp signal. Going to sleep.".[citation needed]

To correct this, service groups will often replace the logic board or power converter, but the actual fix (depending on the model) for the first cause is to replace or remove the left or right ambient light sensors; and for the second cause, disconnect, remove, or replace the heat sensor, or the entire top case which holds the trackpad heat sensor. Alternatively, there are reports which detail success in removing certain sensor kernel extensions or rebuilding the kernel using the Darwin Open Source project after commenting out the relevant sleepSystem() call; though permanent solution of the sleep issue in this manner is little documented.[7]

The 1.67GHz model may suffer from manufacturing or design defects in its display. Initial reports pointed to this only being a problem with type M9689 17" PowerBooks introduced in Q2 2005, but then this problem was also seen in displays replaced by Apple Service Providers in this period (e.g. because of the bright spots issue). The devices were the last 17" models shipped with the matte 1440×900 pixel low resolution display. After many months of usage, the displays may show permanently shining lines of various colors stretching vertically across the LCD. Often this will start with 1-pixel wide vertical lines being "stuck" in an "always-on" mode. Various sites have been set up documenting this issue.[8][9] and a campaign seeks to get Apple to acknowledge that a defect exists. Posts regarding this in Apple forums have been heavily censored. No official word from Apple on the issue.