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My Power Mac G4 MDD won't turn on! Answered

I have a Power Mac G4 MDD that won't turn on.  When you push the power button It lights up, but when you realese the power button the light just fades out. Sometimes even when I get it running it turns itself off after a random amount of time.  Every time I unplug the machine it does it's routine. I am experienced with electronics so feel free to post a comment below!  Thanks!

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kelseymh
kelseymh

Best Answer 8 years ago

This is a common problem with Macs. The internal clock has its own battery backup. If that battery runs down (typically after 3-5 years), the system won't power up. Open the case and you can replace the battery, or you can take it to a shop and pay them to do it.

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ladamsii
ladamsii

Answer 6 years ago

Kelseymh I have an old G4 i haven't turned it on in a while so when I tried the other day i was surprised when it didn't power up at all do you think this could be my problem because I was thinking it was the power supply Im going to try the battery to day do I just put it in or is there a step or two

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kelseymh
kelseymh

Answer 6 years ago

Just replace the battery, close up the shell and turn it on. If you've set it up to get the time from NTP, everything should be just fine. Good luck!

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iApple guy
iApple guy

Answer 6 years ago

This fourm is ancient history. Its fixed now and dual booting 10.5 Leopard, and Ubuntu 12.04. It was a power supply issue.

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iApple guy
iApple guy

Answer 8 years ago

This seems to be the answer to my question!
(And you thought you were to "simple-minded!"

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iApple guy
iApple guy

Answer 8 years ago

I don't think this is the problem... The battery lights up a battery just fine.

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bsischo
bsischo

3 years ago

I realise this thread is ancient but I found a fix. The ide cable that connects the optical drive to the mother board had failed. Apparently there is enough vibration in the machine that over the years, it had worn a spot on the cable out and caused a short.

By removing that cable I was able to get the machine to start again.

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djtempo7
djtempo7

Answer 7 years ago

What was your solution? Mine just started exhibiting this symptom. Was running yesterday. Not today.

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RusSEAL
RusSEAL

8 years ago

I've got an MDD I managed to get used/well-flogged & the 1st item that was always a concern was this very problem- at first I could solve the problem by unplugging & plugging back in which was resetting the Power Supply Unit's [PMU] main reset... After a while, most MDDs blow the unit [capacitor failure from cheap-source manufacturing; go figure, right?] and mine was no exception...

That said- this evening we had a power failure [lightening in the area] and once everything came back up, I thought I had a blown PSU- even though it was a new/refab with SUPERIOR parts [guy on eBay does them- I recommend him HIGHLY] not even 6 month old!

Well- it turns out that some of the MDDs are reeeeally finicky when it comes to power-down or power failure style shutdowns- mine is the 877[?]mhz model and when I noticed 'canuckgirl's' recommendation concerning a "Full PMU Reset" [unplug EVERYTHING- THEN restart] wouldn't you know it- I was able to fire this bad/old boy right up..!

Sadly- if your [iAppleGuy] MDD has not had a PSU change/upgrade, you may be suffering from what's been considered an "inevitable" problem with this model/platform which is a catastrophic PSU capacitor failure...

I hope you're able to get it back up and running- this model has been my favorite so far [and for so long] though a G5 [with a modified/corrected liquid cooling system!] certainly wouldn't be turned down if/when I come across it!

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iApple guy
iApple guy

Answer 8 years ago

Just a side note to keep in mind, read ALL comments before posting one! You must have put effort into that comment, but if you look down below I'm sure you will notice something. Read the comment that was posted July 11 2012 at 1:26 PM:

Ok, I know that this is kind of an "OUTDATED" post, but i figured something out. Sometimes it will turn on... And sometimes it wont. So I finally decided to take it in to someone that I know that repairs computers at a good price. He thinks it is the power supply. But we will soon find out!

iApple guy

So in the end I did replace the power supply... And it works.
So just make sure to read ALL comments first!

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iApple guy
iApple guy

Answer 8 years ago

Thanks for your post! But... I have already tried that.