PowerBook 500 Series Battery EMM Fix

After reading about all the problems people keep asking about regarding 500 series intelligent batteries losing their intelligence, including myself, I've set up this page for your information. Use this information at your own risk; don't blame me if something goes wrong.


Battery Utilities 500Lite 1.02 - Download (Stuffit 5 12K)

This is the Battery Utilities 500Lite freeware Control Strip Module. However, it will only work on a non-PPC upgraded PowerBook.
BU500 Deluxe 2.01 - Download (Stuffit 5 36K)

The BU500 Deluxe 2.01 package which includes the Battery Capacity control strip module.
ResEdit 2.1.3 - Download (MacBinary 465K)

If you don't already have it, you'll need a copy of ResEdit, too.

Resetting the EMM

1. Download the Lind control strip module (see above) for PowerBook 500 series. It's freeware, and it only works on non-upgraded 500 series PowerBooks.

2. Duplicate the CSM and open the copy in ResEdit. Put the original somewhere where you won't confuse it with the copy.

3. There are two or three resources of type MASK. These consist mostly of "FF" bytes with a few "holes" of "00". Fill all the "00" holes with "FF". Save the changes, and quit ResEdit.

4. Put the modified CSM in your "Control Strip Modules" folder (inside your System Folder, of course) and restart.

5. Run the CSM's normal repair process. It will overwrite absolutely everything inside the EMM with factory values.

Your battery will not report its capacity accurately until you put it through at least one full to ZERO discharge from 100% charged state. Try using BatteryAmnesia 1.5.2 to discharge a battery to zero. Ultimately, the only way to fix the problem is to replace the EMM, or buy a new battery. If your computer is still under warranty, including AppleCare, take it to your local Apple authorized dealer and they'll replace the battery free of charge.

Thanks to Lewin A.R.W. Edwards for the repair procedure!


Visit your local comp.sys.mac.portables newsgroup if you have any questions relating to your PowerBook!

Other PowerBook Repair Sites

Apple Powerbook 520 & 540 Powerbook Modifications & Fixes