PowerMac G4 Quicksilver Powers On Doesn't Boot

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phase52010 Author

Level 1

18 points

PowerMac G4 Quicksilver Powers On Doesn't Boot

PowerMac G4 Quicksilver 867Mhz (2001)
Running OS 10.5.8. 1.5Gb RAM.

Ny old machine has been running well. Recently after "shutdown" the machine would hang and I would have to powerdown by pressing the power button.

Did some reading on the topic and it suggested that resetting the PRAM might help. I tried this but have run into a problem.

When I press the powerbutton to turn on the Mac, the Power button lights and the machine turns on, *but then the Powerbutton light goes out*. *Normally it would stay on*. The machine then just sits there and doesn't boot up. Nothing happens, and after a while I power the Mac off using the powerbutton.

I did this again with the PowerMacs door open. The main boards little red light comes on, and the fans are working. However I think the Mac Mouse and the keyboard aren't responding/receiving power.(?). (The little red light under the mac Mouse doesn't come on).

I did further reading and tried pressing the "PMU" button, (just once as advised), to reset the "Power Management Unit".

This didn't improve the situation.

As of this writing the PowerMac will power on, the powerbutton light doesn't stay on, and will not boot up. I've read as many posts as I can without finding anything relevant to resolving the issue.

I've tried booting from various disc's but as I said, I don't think the keyboard is responding.

Any suggestions for what to try next, most welcome.

PowerMac G4 Quicksilver, Mac OS X (10.5.8), 1.5Gb RAM

Posted on Dec 15, 2010 10:07 PM

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Answer 1

Dec 15, 2010 10:33 PM in response to phase52010

Hi, phase52010 -

Welcome to Apple's Discussions.

If you have never replaced the battery in that machine, now is the time to do so. A too-weak or dead battery can cause booting anomalies. The internal battery in that machine has an expected best-case life of about 4 to 5 years, less if the machine is unplugged regularly or for an extended period.

You can get a replacement battery at places like RadioShack for about US$18, cheaper on-line.

After replacing the battery, reset the PMU once more.

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Answer 2

phase52010 Author

Level 1

18 points

Dec 16, 2010 12:47 AM in response to Don Archibald

Don, thank you for your reply.
I believe I replaced the battery recently, perhaps in the last 2 years? I'll have to check.

Question: If I remove the battery, and reset the PMU once, should I be able to poweron the Mac and get it to boot? I understand that the battery supplies power for ther memory when the sytem is powered off, and that I'd lose any changes. I'd just like to get the system to boot up, which it currently isn't doing.

Robert.

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Answer 3

Dec 16, 2010 6:00 AM in response to phase52010

Hi, Robert -

It may boot successfully that way, although the date and time may be off.

The internal battery provides power to maintain PRAM and clock chip settings when the machine is unplugged; as long as the machine is plugged in to live power, a trickle current is used from that rather than the battery (which is the reason for a small spark appearing whn plugging a machine in).

However, not everything is turned on at the same instant - there is electronic switching circuitry that, once initiated via the on button, sequences the power on to various sections. For some reason the presence of a less-than-adequate battery can affect that sequencing negatively. Sometimes removal of a poor battery will allow normal startup.

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Answer 4

phase52010 Author

Level 1

18 points

Dec 17, 2010 4:59 PM in response to Don Archibald

Hi Don;
thank you for that information. At the moment I'm still not having any success with getting the machine to boot. I left it off for an hour with the battery taken out, but all that happens at powerup is that the unit turns on, the powerbutton light goes out and that's about it. I'll try pulling the battery and leaving the G4 unplugged over the weekend (48 hrs) as I read various recommendations to leave computers with this issue disconnected for 24 hours. Anyway, I'll see how that goes and report back.
Robert.

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Answer 5

BDAqua

Level 10

239,213 points

Dec 17, 2010 5:56 PM in response to phase52010

Hi Robert, just askin' are all the peripherals unplugged?

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Answer 6

phase52010 Author

Level 1

18 points

Dec 17, 2010 7:18 PM in response to BDAqua

No problem asking.

Yes, absolutely everything is unplugged.

I've taken the G4 out from under the desk where it normally resides and placed it on coffee table to make access easier. I only connect keyboard, mouse and screen when attempting to power on.

Right now, everything is disconnected for the 48 hr wait period.

Robert.

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Answer 7

BDAqua

Level 10

239,213 points

Dec 17, 2010 7:51 PM in response to phase52010

Thanks. 🙂

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Answer 8

phase52010 Author

Level 1

18 points

Dec 20, 2010 5:31 PM in response to BDAqua

I've left the powermac G4 powered down with the battery out, and everything disconnected for well over 48 hrs. (close to 72).

I reconnected the monitor, the keyboard and the mouse, re-inserted the battery, connected the power and powered on.

nothing. same as before.

the power button light comes on, then goes out and nothing else happens.

i've tried powering on with various keys depressed, but nothing happens.
can't get it to boot from the DVD-ROm drive, can't get anything to happen.

any suggestions?

because my solutions I've read all say something along the line of "boot from the ... CD".

many thanks.

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Answer 9

BDAqua

Level 10

239,213 points

Dec 20, 2010 5:36 PM in response to phase52010

Sorry to hear, it sounds like the Power Supply, see these...

http://discussions.apple.com/thread.jspa?threadID=1146533

http://discussions.info.apple.com/message.jspa?messageID=10411174

http://sci.tech-archive.net/Archive/sci.electronics.repair/2006-01/msg01670.html

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Answer 10

phase52010 Author

Level 1

18 points

Dec 20, 2010 5:43 PM in response to BDAqua

Thanks for all the links, I'll print them out and read through them.

It hadn't occurred to me that it could be the actual power supply.
How long do there last on average? (If you know).
The G4 is now about 10 years old, so the power supply has had a good workout.

Thanks. Robert.

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Answer 11

BDAqua

Level 10

239,213 points

Dec 20, 2010 5:47 PM in response to phase52010

I don't know the average, but 10 years seems longer than average, but it depends on so many factors... ambient temperature, dust, usage, etc.

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Answer 12

phase52010 Author

Level 1

18 points

Dec 20, 2010 6:11 PM in response to BDAqua

I have to admit that the G4 was having some odd "shutdown" issues.

I'd click on "SHUTDOWN", everything would finish, the Desktop image would still be there, there's be no little spinning icon, and nothing else would happen. I'd have to use the powerbutton to power off.

Due to the time of year and (lack of) cash reserves, I will have to put this little problem on hold for the time being. Lucky for me I purchased an Intel Mac-Mini just a few weeks back, so I can still do what needs to be done.

Thanks for the help BDAqua. Mery Christmas/Happy Holidays and a Happy new Year.

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Answer 13

BDAqua

Level 10

239,213 points

Dec 20, 2010 6:17 PM in response to phase52010

OK, good luck & Happy Holidays! 🙂

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