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unexplained shut down

Message #1 - Posted 2005/02/11 - Charlie

My dual 1.25 G4 is always on (or asleep) unless I go away for a few days. Yesterday I came home from work and the computer was shut down. No other equipment or clocks were off to explain it.

When I restarted, the time & date was set to 1969 and I had to reset it. I realize the latter may indicates a battery problem, but why the shut down? Can battery problems be caused from power spikes? Unfortunately, the thing is not on a surge protector.

The only thing I did to the system is upgrade from 10.3.6 to 10.3.7 a few days ago.

Message #2 - Posted 2005/02/11 - morenuf

Previously, Charlie wrote:

My dual 1.25 G4 is always on (or asleep) unless I go away for a few days. Yesterday I came home from work and the computer was shut down. No other equipment or clocks were off to explain it.

When I restarted, the time & date was set to 1969 and I had to reset it. I realize the latter may indicates a battery problem, but why the shut down? Can battery problems be caused from power spikes? Unfortunately, the thing is not on a surge protector.

The only thing I did to the system is upgrade from 10.3.6 to 10.3.7 a few days ago.

A power spike (or power going off & on a few times) could have done something like this. If all is okay currently, all well and good,but if it happens again, or you still have a problem read on.

You may have to replace the PRAM battery or reset the PMU or both.

Not really sure if this is your circumstance, but here a possibility for an explanation.

The PMU (Power Management Unit) controls the PRAM and many startup and pawer functions. The reset for the PMU is a button on the motherboard itself near the battery. The darn thing is very susceptible to voltage transients including static electricity if any components on the motherboard are touched.

I have had to "reset the motherboard" as some refer to it by resetting this PMU. My G4s on these occasions refused to startup, no video, chime etc. First time it happened I thought I was in deep trouble.

On two occasions this happened I was inside the G4 changing hard drives. So I could have (and likely did) introduced some stray static charge despite my care to ground myself.

But on three other occasions this happened while G4s were off and major electrical storms occurred. The G4s were off but still plugged in during the storms.

You might have a problem with the PMU. One thing they specifically mention is NOT to press the PMU more than once as it may leave the PMU in unhappy state and this can drain the PRAM battery in two days instead of 4-5 years.

When the PRAM battery is down or dead loss of dates, various setting like the key repeat rate, mouse speed etc are all controlled by the PRAM.

You may have to replace the PRAM battery if voltage is below 3.6 volts. It is available at Radio Shack @ $10 or online at places like OWC (Other World Computing) @$7. These batteries normally last 3-5 years.

G'Day

Morenuf

morenuf@nobodyhome.com.invalid

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