Power Controller

The PowerBook G4 computer can operate from a 15 volt power outlet on an airline, but for safety reasons, the computer will not allow battery charging. In order for the computer to detect the connection to airline power, the airline power cable should have a sense resistor of 24.3K ohms connected between the power plug's shell and ground.

The PowerBook G4 computer has a new variable speed fan control circuit and a new thermal circuit that will force the unit to sleep if the processor temperature exceeds 85 degrees Celsius. The circuit remains active during sleep so that it can continue to poll the temperature.


The power management controller in the PowerBook G4 computer is a custom IC called the PMU99. It supports several power-saving modes of operation, including idle, doze, and sleep. For more information, see "Power-Saving Features" (page 18).

Note: In the device tree, the power controller is named "via-pmu".

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DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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