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User profile for user: infestedsmith
infestedsmith Author
User level: Level 1
0 points

PowerMac G4 Quicksilver won't turn on

My Dad owns a PowerMac G4 Quicksilver 867Mhz computer, with default parts installed, and no add-ons whatsoever. He was using it one night, and it was running fine, and then the next day, he tried to turn it on, and it wouldn't do anything. The light stays on while you're pushing on it, but turns off as soon as you release it. I have tried all the following:

CUDA Switch: Tried a dozen different diagnostic test with this switch, none worked.

Power Supply: Bought a fine new working power supply, switched them out, didn't work.

PRAM Battery: Took a brand new PRAM battery and put that into the computer, didn't work.

Power Cord: Switched out the old power cord with a fine working one, didn't work.

So after all that, what on earth can I do now? If I have to replace the Logic Board I can, but I'd be very surprised if it was the problem. We had no storms, no power surges, no "brown-outs" or anything that would disrupt or damage my Dad's computer, so I'm at a loss as to what it could be. If anyone has any ideas, EVEN if I've already tried them, please post. Thanks.

Power Mac G4 933 Mhz Quicksilver 2002, Mac OS X (10.4.10), 512MB RAM/60GB HD/128MB VRAM GeForceTi4600

Posted on Apr 8, 2008 6:55 AM

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User profile for user: Limnos
Limnos
User level: Level 10
419,863 points

Posted on Apr 8, 2008 7:06 AM

Well you tried a new PRAM battery, but did you test it? I once had somebody give me a computer with a new battery (saw him take hte old one out and put the new one in) and the new battery was dead. If you have a digital multimeter you can check the condition of your present battery. It should read at least 3.2V if it is the 3.6V half-AA battery type. Ideally this should be measured while the battery is under load; added recommendation from Hans777:

I have recently found out that an exhausted battery will still indicate >3.6 V with a high internal resistance VM.

Checking incircuit: powercord disconnected press PMU reset button for >about 5 sec before measuring.

Checking outside: load the battery with a 1500 Ohm resistor when measuring.
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User profile for user: Limnos
Limnos
User level: Level 10
419,863 points

Apr 8, 2008 7:06 AM in response to infestedsmith

Well you tried a new PRAM battery, but did you test it? I once had somebody give me a computer with a new battery (saw him take hte old one out and put the new one in) and the new battery was dead. If you have a digital multimeter you can check the condition of your present battery. It should read at least 3.2V if it is the 3.6V half-AA battery type. Ideally this should be measured while the battery is under load; added recommendation from Hans777:

I have recently found out that an exhausted battery will still indicate >3.6 V with a high internal resistance VM.

Checking incircuit: powercord disconnected press PMU reset button for >about 5 sec before measuring.

Checking outside: load the battery with a 1500 Ohm resistor when measuring.
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User profile for user: Dale Weisshaar
Dale Weisshaar
User level: Level 6
15,872 points

Apr 8, 2008 10:29 AM in response to infestedsmith

infestedsmith wrote:
The light stays on while you're pushing on it, but turns off as soon as you release it. I have tried all the following:

Still sounds like a battery issue;
I would check it first. When mine went, I had no response from my Mac at all; just a light on my power button; absolutely no boot at all.
Check out things in Texas Mac Man's Battery, PRAM, PMU tutorial on the subject. His tutorial is a little dated (don't believe it even mentions G5's) but the info in it, except SMU not being included, still applies.

Cheers! DALE

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User profile for user: Dale Weisshaar
Dale Weisshaar
User level: Level 6
15,872 points

Apr 8, 2008 10:32 AM in response to infestedsmith

Try this if tutorial doesn't help;
-I found this on a Mac site. Sometimes computers lose their mind. Don't ask me why or how it happens but it does. Sometimes you simply have to totally discharge the computer. One thing I have learned about the Blue and white and the Gray G4 Macs is that sometimes pushing the PMU is not enough. If your machine is dead, then try the following.
* Unplug the unit.
* Remove the battery
* Push the PMU switch (count to 5 slow)
* Push the start button on the front of the Mac (count to 5 slow)
* Let the unit sit for 15-30 minutes
* Replace the battery
* Plug it back in, and push the start button

If it doesn't work I usually repeat the steps above, pull the RAM, and let it sit longer. If it doesn't work after this, it is take it to the shop time.
(this is at the end of the tutorial)
Dale
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User profile for user: japamac
japamac
User level: Level 7
24,400 points

Apr 8, 2008 8:56 PM in response to infestedsmith

infestedsmith wrote:
How could it possibly be my battery, when it's been working flawlessly on my other G4 PowerMac for several months since I bought it?

An often heard comment here. And, as often, a new battery solves the problem.....

I never really understood the resistance to an inexpensive, potentially helpful troubleshooting technique.

Has your other G4 been unplugged for days or weeks? If not, it hasn't really used the battery, and the battery could be fine. If it has been unplugged, it is drawing down the battery. A simple voltage test will confirm this. Without the test, there will always be doubt in the collective mind of the forum here, that the battery is good....
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User profile for user: infestedsmith
infestedsmith Author
User level: Level 1
0 points

Apr 9, 2008 7:17 AM in response to japamac

I'm not resisting, in fact, I've been trying batteries, and trying to get a tester for the ones I have, I was simply wondering how the battery could work on my new machine, and not work on the older one. My G4 computer is always plugged in, and is usually on too.

My Dad purchased another 3.6v Lithium Battery from our local electronics store, so hopefully this will solve the problem, also, the battery from the old machine was discovered to be dead. Had to get them to find out, as our voltage tester's battery was dead. :P

I installed the brand-new and tested battery, and it didn't work, so I'm going to perform all the different resets and zaps and whatnot to see if that gets things rolling.

Thanks for the help, if anyone has any more helpful comments, I can use all I can get. Thanks!
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User profile for user: infestedsmith
infestedsmith Author
User level: Level 1
0 points

Apr 9, 2008 8:30 AM in response to infestedsmith

Okay, tried the new battery, didn't work, and I did the discharge/reset thing by removing the battery and RAM, pressing the CUDA switch for 5 seconds, and then closing the hatch, and pressing the power button for 5 seconds, and waiting for 15-30 minutes, putting the RAM and battery back in, and then pressing the power button. Didn't work. No sound, no nothing. Now what do I do?
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PowerMac G4 Quicksilver won't turn on

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