Power Mac that thinks it's a portable: logic board defect the cause?

Regarding our item last time about the "Running on reserve battery power" message appearing on a Power Mac G4, Adam Turetzky writes: "I had this same problem six months ago and even started a MacFixIt Forums thread on the matter. Apple sent a repair guy out and they replaced the logic board and the processor. The tech said a chip or sensor that monitors the case housing "close" switch (like your refrigerator light) had burned out. The only way to run the machine when this happens is to leave the side case door down and open. Otherwise it shuts off. In any event, the logic board replacement fixed the problem." Adam theorizes that losing power while the Mac is in "deep sleep" may trigger this problem. We seem to recall posting something about this "open door policy" before, but could not locate the link.

Thomas Koons adds: "Mac OS 9.0.4 has a new power manager which works with PowerBooks as well as desktop Macs. It can tie directly into a UPS's USB port for communication with the UPS for power management. This way no software need be installed for the backup battery to shut the computer down. OS 9.0.4 will recognize when the UPS is turned on and this kicks in the PowerBook-style battery features which will then make your desktop act like a PowerBook running on a battery. The message the users have seen is perfectly normal if the G4 was running on an UPS battery when power goes out in the building. In the case of the error message appearing, perhaps a power fault happened which corrupted something."

However, Ian Campbell writes: "Recently a new G4 450 exhibited this symptom right out of the box. I contacted Apple Support who had me send the board directly to Apple. I was advised that Apple has just been made aware of the problem and are trying to solve it quickly by testing these boards directly. It would appear that a power surge is not the original condition as I now have had 2 new CPUs show the same problem. Replacing the logic board has corrected the issue."

Resources

item last time

MacFixIt Forums thread

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