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G4 power-up

Message #1 - Posted 2005/06/26 - Ron Lee

Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up.

Sleep and shut down are fine. Only unplugging is a problem.

I have been having other similar problems recently with this computer but it seems to have resolved into this at this time. Here are the specs.

G4 Gigabit Ethernet dual processor 450
896 meg ram
OS X 10.3.9

Thanks for any advice and/or insight.

Ron

Message #2 - Posted 2005/06/26 - Andreas Rutishauser

Salut Ron

Previously, Ron Lee wrote:

Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up.

G4 Gigabit Ethernet dual processor 450
896 meg ram
OS X 10.3.9

when has the battery been replaced the last time?

Cheers
Andreas

MacAndreas Rutishauser, <http://www.MacAndreas.ch> EDV-Dienstleistungen, Hard- und Software, Internet und Netzwerk Beratung, Unterstuetzung und Schulung <mailto:andreas@MacAndreas.ch>, Fon: 01 / 721 36 47

Message #3 - Posted 2005/06/26 - Ron Lee

Previously, Andreas Rutishauser wrote:

Salut Ron

Previously, Ron Lee wrote:

Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up.

G4 Gigabit Ethernet dual processor 450
896 meg ram
OS X 10.3.9

when has the battery been replaced the last time?

Cheers
Andreas

Battery is fairly new and checks to 3.6v.

Ron

Message #4 - Posted 2005/06/27 - peter.bozek

Ron Lee wrote:

Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up.

Sleep and shut down are fine. Only unplugging is a problem.

...

G4 Gigabit Ethernet dual processor 450
896 meg ram
OS X 10.3.9

We have the same machine (less memory, though) and are witnessing the same problem. It gets worse over time, now it sometimes does not start if we restart the machine - so it does not seem to be caused by onboard battery.

We were not able to find a reason - as a workaround we never switch off the computer, only put it to sleep.

Message #5 - Posted 2005/06/27 - John Albert

Ron Lee wrote:
<< Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up. >>

And Peter Bozek replied:
<< We have the same machine (less memory, though) and are witnessing the same problem. It gets worse over time, now it sometimes does not start if we restart the machine - so it does not seem to be caused by onboard battery. We were not able to find a reason - as a workaround we never switch off the computer, only put it to sleep. >>

I have a very late-model g4 1.25 dual-processor (one of the last g4s made). It provides my only experience with the g4 models, so my experiences may or may not be relevant to yours.

A few times I have had the machine either go to sleep, or shut down, and seem to enter a "comatose" state from which it would not power up. When power was applied to the power cord, and the power-on button pressed, the button would illuminate, but pressing it did nothing. Absolutely no signs of life from within the box. Nothing at all, except the lighted power-on button.

The only way I was able to revive it was to open the side, drop the motherboard down, and locate and press the small round button in the square "holder". After doing so, it came right to life and behaved normally again.

I know older Macs had something called a "CUDA" switch that could be used to reset the PRAM. I _think_ it may now be called the "PMU" (power management unit?) button.

You might try opening the case, locating this button (pretty small), and pressing it ONE time for a period of 30 seconds to a minute. Then try rebooting.

- John

Message #6 - Posted 2005/06/27 - Ron Lee

Previously, John Albert wrote:

Ron Lee wrote:
<< Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in
the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up. >>

The only way I was able to revive it was to open the side, drop the motherboard down, and locate and press the small round button in the square "holder". After doing so, it came right to life and behaved normally again.

I know older Macs had something called a "CUDA" switch that could be used to reset the PRAM. I _think_ it may now be called the "PMU" (power management unit?) button.

You might try opening the case, locating this button (pretty small), and pressing it ONE time for a period of 30 seconds to a minute. Then try rebooting.

- John

John,

I have done this on several occasions. Sometimes this seemed to work but not always. This computer has been to the local Apple shop. When they reset the PMU it powered up and ran for two days with no problems. They said there was static on the logic board and wanted to replace it. I brought it home and it would not power-up! I bought a board on eBay and replaced it myself and it did not power up until it sat for a while.

Is there something that loses its power when unplugged but recharges after power is on for a while? Something in the power supply?

I am baffled. Thanks for your reply.

Ron

Message #7 - Posted 2005/06/29 - David Cartwright

"Ron Lee" <rgl4508@earthlink.net> wrote in message news:rgl4508-B700EE.13053526062005@news.east.earthlink.net...

Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up. Sleep and shut down are fine. Only unplugging is a problem.

I once had a Mac IIfx that did this.

If it's not the battery (and from other posts it sounds like it isn't) it might be as simple as a dry joint or similar in the switch-mode power supply. Most desktop computers have power supplies that are "always on", which means that the "side" of the supply closest to the mains supply is on power whenever it's plugged in. You may find that it's only when the mains "side" of the PSU has a joint somewhere that only contacts when it's nice and warm.

What happens if you unplug it for just a few seconds, then plug back in and try to start up? If it starts up then the above may be the problem. If it doesn't, then forget everything I've said :-)

D.

Message #8 - Posted 2005/06/29 - Ron Lee

Previously, David Cartwright wrote:

"Ron Lee" <rgl4508@earthlink.net> wrote in message news:rgl4508-B700EE.13053526062005@news.east.earthlink.net...

Lately I have been having problems with power-up on my G4. I have in the past always powered down and unplugged the computer when there is lightning in the area. Now I can not power-up immediately after plugging in the computer. After it sits for several hours then it will power-up. Sleep and shut down are fine. Only unplugging is a problem.

I once had a Mac IIfx that did this.

If it's not the battery (and from other posts it sounds like it isn't) it might be as simple as a dry joint or similar in the switch-mode power supply. Most desktop computers have power supplies that are "always on", which means that the "side" of the supply closest to the mains supply is on power whenever it's plugged in. You may find that it's only when the mains "side" of the PSU has a joint somewhere that only contacts when it's nice and warm.

What happens if you unplug it for just a few seconds, then plug back in and try to start up? If it starts up then the above may be the problem. If it doesn't, then forget everything I've said :-)

D.

Turned off power strip for 15 seconds and then back on. Computer powered up just fine. So the power supply is probably the culprit in this? Now I need to find an inexpensive power supply, figure the odds on that. Don't know if computer is worth it, but I can't afford another one right now.

Thanks for your help.

Ron

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