Troubleshooting the PowerBook: Miscellaneous

I often read and hear about "processor cycling." What is it? How does it help?

When should I put my PowerBook in sleep mode versus shutting it down?

My PowerBook is always clicking. Why?

What's the proper way to reset the Power Manager on each type of Macintosh PowerBook computer?

I often read and hear about "processor cycling." What is it? How does it help?

Processor cycling is a clever way of preserving power. Under normal circumstances, your PowerBook's processor is continually waiting for you to instigate some command. Consequently, it is very active -- this consumes battery power. Processor cycling, on the other hand, will put your processor to rest while the PowerBook remains awake. In general, it is suggested that processor cycling be kept on in order to prevent the processor from being on all the time.

When should I put my PowerBook in sleep mode versus shutting it down?

There are only five instances when it should be shut down. Otherwise, let it sleep! They are:

When you attach or remove a second (external) monitor.
When you want to make it a part of the SCSI chain of another computer.
When restarting it with a different assortment of extensions and control panels.
If it's a PB Duo, then it must be shut down before inserting it into a Duo Dock.
When the PowerBook is running off the battery and it won't be used for more than 30 minutes.

The PowerBook Duos automatically go to sleep when they are closed.

My PowerBook is always clicking. Why?

The clicking could come from two different sources. The first (and most common) is the machine's circuitry working with the speaker. After any sound has played, the Mac cuts off battery power to the speaker, thus endowing you with a few extra minutes of working time. The little click you hear is the juice being turned off to the sound chip and speaker.

The other click you hear, primarily on newer PowerBook models, is the sound of the hard drive's heads being parked aside. This is characteristic of the IBM-made internal hard drives that were used on the later PowerBook models.

What's the proper way to reset the Power Manager on each type of Macintosh PowerBook computer?

PowerBook 100 and 500 Series:
1. Remove the AC Adapter and the battery.
2. Let the unit sit without power hooked up for 3 to 5 minutes.
3. Depending on which PowerBook model you have, do one of the following:

If it's a PowerBook 160, 165, 180 series, stop here.
For the PowerBook 140, 145, 170 series, use two paper clips to simultaneously press and hold both recessed buttons (commonly known as the reset and interrupt buttons) located next to the power button on the back panel of the PowerBook for approximately 5-10 seconds.
For the PowerBook 150, either hold down the Control, Command (Apple), and Power On keys at the same time for approximately 5-10 seconds, or using a paper clip push the reset switch on the back.
For the PowerBook 500 series, hold down the Control, Command (Apple), and Power On keys at the same time for approximately 5-10 seconds.

PowerBook 200 Series:
The Power On button above the keyboard is seen as a keyboard key and executes power-on functionality, but does not reset the Power Manager. You can only use the rear power switch -- not the power on button above the keyboard. Press the power button on the rear of the 200 Series computers for 30-45 seconds.

The above procedures reset power to the Power Manager chip but it does not reset the Power Manager code. These procedure will reset PowerBooks that have had system crashes, and can fix some power-related problems. These procedure will remove a RAM disk and its contents.

The Power Manager code can be fully purged by having a authorized service technician disconnect the internal backup battery and let the unit sit for 10 minutes with all power removed (the battery pulled and the AC Adapter disconnected). This will force the PowerBook to reload a fresh copy of the code from the system software.

PowerBook 190 and 5300 Series:
Resetting the Power Manager is similar to the procedure for the 100 series except that the machine does not have to sit for several minutes. Remove the battery and AC power and hold down the reset button for about 30 seconds. This can solve a variety of problems, all having to do with odd combinations of a PowerBook running with battery but not AC power, with AC power but not with a battery, and not starting at all with any kind of power connected.

©1996 by MacintoshOS.com
Apple Computer, Inc. in no way endorses or is affiliated with MacintoshOS.com. Apple, the Apple logo, and Macintosh are registered trademarks and Mac OS is a trademark of Apple Computer, Inc.

Much of the information contained herein has been extracted from Elliotte M. Harold's incredible FAQ lists. We thank and commend him for his invaluable service to the Macintosh world.