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iBook not resetting PRAM

Message #1 - Posted 2006/07/19 - mufuti

hello there,

my ibook (g4, 1.3ghz) is not resetting the pram anymore when pressing command-option-p-r at start-up and i have no idea why. i tried it a thousand times at different times (before, while, after the chimes). resetting the nvram via open firmware prompt did work. however, i did not get to the open firmware prompt by command-option-o-f, but after resetting the pmu a few times via shift-option-power. now the system boots into the firmware prompt every time. it shows an "invalid memory access at .." message at the top. when i managed to get to the firmware prompt before it showed diffent messages like "floating point unavailable" and "illegal instruction".

the reason why i am trying to reset the pram is that the system was stopping with a black screen when starting up. i did manage to reset the pram once in the beginning, my system was booting up at froze with a white screen "you have to switch off.." and from then on i got the funny behaviour described above. booting with "C" or option key also does not work.

any ideas? hardware fault?

thanks, meinhard.

Message #2 - Posted 2006/07/20 - Fred McKenzie

Previously, mufuti@gmail.com wrote:

my ibook (g4, 1.3ghz) is not resetting the pram anymore when pressing command-option-p-r at start-up and i have no idea why. i tried it a thousand times at different times (before, while, after the chimes).

Meinhard-

You hold down the keys immediately when starting or restarting. If you wait for the chime, it is clearly too late.

How many chimes did you hear before you let go of the command-option-p-r? The reset occurs after the second chime. I usually wait for the third chime to be sure. An Apple Help Desk person once told me to wait for five chimes, but that was for an old LC III machine.

Fred

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