Why Macintosh Portable & PowerBook Computers Won't Sleep

TECHINFO-0008000

TOPIC

Sometimes Macintosh Portable and PowerBook computers running any version of System 7.x will not go into Sleep mode, regardless of the sleep time settings in the Portable or PowerBook control panel. Why is this?

DISCUSSION

The following activities may prevent the Macintosh Portable or PowerBook computer from sleeping UNLESS a low-power condition occurs:

Common Causes

• The "Stay awake when plugged in" option is selected in the Portable control panel, AND you are plugged into AC power.

• The PowerBook control panel slider selections are set to "Never sleep."

• The serial driver is open and active.

• AppleTalk is active (Check the Chooser). Note: A volume does not need to be mounted nor do you need to be connected to an AppleTalk network.

• When an internal modem's auto-answer is on.

Further Troubleshooting Tips

• PowerBook 5300 and 190: There is a known issue with the password security feature on the PowerBook 5300 and 190 series computers. If you open the Password Security control panel and set the password security is turned on and is set for ask password on wake, the unit will not sleep. One workaround is to turn off the "ask for password on wake" feature. If this is done, the PowerBook will be able to sleep. This issue can be resolved by installing the System 7.5 Update 2.0 (or later system software) which includes the Password Security 1.0.3 control panel.

• Check to make sure that there are no INITs (extensions) or control panels in the System Folder that may be causing the computer to assume that the system is busy. (For example, the FocalPoint II INIT has been shown to cause this; others may also.)

• Make sure there are no applications currently running which would keep the system busy. (For example, Microsoft Word's automatic repagination option will keep the system awake.)

• An extension called Insomnia came on the Install Me First disk with some versions of the system software. If this extension is mistakenly put into the Extensions folder in the active System folder on the hard drive, the PowerBook will not sleep. It should be removed from the hard drive. Insomnia is an extension that keeps the PowerBook from going to sleep during the installation process when starting from the Install Me First disk.

Technical Details

For the more technically inclined, the following system activities also prevent the machine from entering the sleep or rest mode:

• A call to Read or Write through IOCore.

• Calling PostEvent.

• OSEventAvail returning true.

• Generating a sound.

• Execution of an ADB completion routine.

• A call to SetCursor (that really changes the cursor).

• The watch cursor is the active cursor.

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