How To Reset a Pram G4 Powerbook
The Mac operating system uses parameter random access memory (PRAM) to store initial settings and preferences such as date, time, cursor blink rate, keyboard, mouse, monitors and sound. Occasionally, the computer may freeze or crash, indicating that the PRAM may be corrupt, thereby affecting basic functions. Resetting the PRAM (also called zapping) restores the settings and preferences to factory defaults, which may resolve the problem. These settings can be selected after the computer starts up normally.
Shut down your computer.
Press and hold the following keys: "Option," "Command" (Apple logo), "P" and "R".
Turn on your computer while continuing to hold down the keys.
Continue holding down the keys as the computer starts. Wait until you hear the start-up sound twice.
Release the four keys and wait for your computer to finish starting.
Tips & Warnings
- Some recommend waiting for the start-up sound to chime three times. When you release the keys, the computer will continue its system start-up process.
- According to the Apple Support website, PowerBooks and iBooks may need to have the PMU (Power Management Unit) reset if resetting the PRAM doesn't resolve the problem. See Resource 1 for more information.