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dying PRAM battery?

Message #1 - Posted 2005/10/06 - Hugh Chaloner

Hi,

I'm noticing a few things on restart on a 39-month-old powerbook - the screen brightness parameter keeps changing, and the volume resets. I've also noticed a few other anomalies during day to day operation and am wondering if this could be the death of a PRAM / backup battery? The machine is more than three years old.

PowerBook Ti 800MHz.

Thanks,
Hugh

Message #2 - Posted 2005/11/10 - Shawn Hirn

Previously, Hugh Chaloner wrote:

Hi,

I'm noticing a few things on restart on a 39-month-old powerbook - the screen brightness parameter keeps changing, and the volume resets. I've also noticed a few other anomalies during day to day operation and am wondering if this could be the death of a PRAM / backup battery? The machine is more than three years old.

PowerBook Ti 800MHz.

A dead giveaway is the clock. If you shut down your Powerbook and remove the main battery, does the clock report the time accurately after its powered up again? If the clock loses its time, its a dead giveaway that the PRAM battery's dead.

Message #3 - Posted 2005/11/11 - pailface88

I am not sure of this concerning all pewerbooks but many or them at least are designed such that you can change your main battery for a fresh one while the computer is in Sleep mode. The PRAM battery supplies power to the RAM contents while it is sleeping. A good PRAM battery should be able to maintain the computer for 4 minutes whil in sleep mode. The sleep LED should remain blinking for that long. Typically when a PRAM battery is on its last legs, it may still keep the clock accurate but it may occasionally screw up other PRAM settings.

If you want to know the condition of your PRAM battery, put the computer to sleep and remove the power cord aned the main battery and see how long the Sleep LED blinks. If it quits blinking very quickly then your PRAM battery is done. They are a rechargable type of battery as opposed to desktop computer PRAM batteries which are not.

I don't know if this is how your powerbook model funtions but I suspect it would say so in the operators manual.

Message #4 - Posted 2005/11/13 - Joe Heimann

pailface88@yahoo.com wrote:

I am not sure of this concerning all pewerbooks but many or them at least are designed such that you can change your main battery for a fresh one while the computer is in Sleep mode. The PRAM battery supplies power to the RAM contents while it is sleeping. A good PRAM battery should be able to maintain the computer for 4 minutes whil in sleep mode. The sleep LED should remain blinking for that long. Typically when a PRAM battery is on its last legs, it may still keep the clock accurate but it may occasionally screw up other PRAM settings.

This does not apply to 12" PowerBooks and all iBooks. Those models do not have a backup/PRAM battery at all. They also need to have their main batteries replaced while shutdown, or attached to their power adapter.

Joe

If you want to know the condition of your PRAM battery, put the computer to sleep and remove the power cord aned the main battery and see how long the Sleep LED blinks. If it quits blinking very quickly then your PRAM battery is done. They are a rechargable type of battery as opposed to desktop computer PRAM batteries which are not.

I don't know if this is how your powerbook model funtions but I suspect it would say so in the operators manual.

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