From the Read Me included with this software:
Important Information About the PowerBook 1400 PMU Updater
This document describes the PowerBook 1400 PMU Updater. You may want to print this document for reference.
IMPORTANT The PowerBook 1400 PMU Updater is preloaded on your hard disk in the manufacturing process. If you reinstall the system software, you must install this extension separately if you are using System 7.5.3 or System 7.6. Be sure to save this disk (or a copy of the PowerBook 1400 PMU Updater) for this purpose.
What Is the PowerBook 1400 PMU Updater?
The PowerBook 1400 PMU Updater is a system extension that remedies two situations which potentially can occur in some Macintosh PowerBook 1400 computers. The conditions are: * the contrast controls on the computer operate incorrectly, so that pressing the upward-pointing end of the control reduces contrast and pressing the downward-pointing end of the control increases contrast. * the brightness controls on the computer operate incorrectly, so that pressing the upward-pointing end of the control reduces brightness and pressing the downward-pointing end of the control increases brightness.
Who Needs to Use the Updater?
The PowerBook 1400 PMU Updater corrects the conditions noted above but does not change other parts of the system software or hardware. If you reinstall the system software (System 7.5.3 or System 7.6), be sure to install the Updater on your computer after the system installation, even if you have not experienced these problems.
To install the Updater, follow these steps.
1. Drag the Updater to the icon of the System Folder on your hard disk and click OK in the dialog box that appears.
2. Restart the computer.
When the computer starts up, the Updater automatically updates the parts of the system that potentially could cause the situations noted above.