Mac Mini Wont Power On

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Level 1

8 points

Mac Mini Wont Power On

I recently moved house, before which my mini was working flawlessly. After the move set up the machine and went to power on, and nothing.

After checking fuses etc. i tracked down a friend with a power supply and tried that. The machine power on and chimed, and so i assumed it was a power supply issue.

I got a new power supply today, plugged it in and the machine burst into life. It worked fine for an hour and a half while doing software updates etc. so several reboots and power cycles.

I then decided to move the machine into the other room after which exactly the same problem occurred. The machine will now not power on, no light, no chime etc.

It seems really odd that it worked fine for an hour or so on the new adaptor. Ive stripped the machine apart, cleaned everything, put it back together and still no luck with either power supply.

Has anyone got any ideas for fixing this machine, as my only other option is to strip it for parts, which seems such a shame for what was a great little computer, and could have been put to good use turning my parents into "Switchers".

Thanks in advance

PPC Mac Mini, Mac OS X (10.5.3)

Posted on Jun 18, 2008 12:33 PM

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Answer 1

cfane Author

Level 1

8 points

Jun 18, 2008 3:00 PM in response to David Dellinger

Unfortunately ive moved back home and so im not able to try my friends power supply. Secondly id be slightly cautious to, as im wondering whether my mac mini has blown my second power supply. I tested the first, and had some really strange voltages on the output, although im not sure if there are an protection mechanisms requiring grounding etc. before giving the regular output voltages.

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Answer 2

AndyO

Level 6

17,064 points

Jun 18, 2008 12:59 PM in response to cfane

Welcome to Apple Discussions!

If this is a PPC mini as your sig line suggests, it may be that the battery which powers the parameter RAM is low. A PRAM reset might help:
-Shut down the computer.
-Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in the next step but one.
-Turn on the computer.
-Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
-Hold the keys down until the computer restarts and you hear the startup sound for the second time.
-Release the keys.

If that doesn't help you, it could be the power management unit, in which case a reset (as follows) might resolve this (do not perform this if the unit is an Intel model):
-Unplug all cables from the computer, including the power cord.
-Wait 10 seconds.
-Plug in the power cord while simultaneously pressing and holding the power button on the back of the computer.
-Let go of the power button.
-Press the power button once more to start up your Mac mini.

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Answer 3

cfane Author

Level 1

8 points

Jun 18, 2008 1:25 PM in response to AndyO

unfortunately ive already tried the PMU reset, and the machine wont power on, so im unable to try the PRAM reset.

The PRAM battery just looks to be a CR2032, is it worth changing it ? would a PRAM issue prevent the unit from powering on ?

Thanks

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Answer 4

Jun 18, 2008 2:10 PM in response to cfane

Hi,
Well, my first suggestions of resetting the PRAM and replacing the battery have already been tried.
Sorry to hear that.

Is it possible to borrow your friend's power adaptor again? If it's working, you could zap PRAM at least.

If your friend's power adaptor still works, tie a string around the two cables for your friend's power adaptor (so you can remember the parts that are his/hers) and swap out just the power cord.

Try turning the power connecter 180° where it connects to the computer.

Good luck!

David

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Answer 5

Jun 19, 2008 1:27 PM in response to cfane

Ok, just wanted to check. It sounds like it might be the actual wiring in your house. You indicate you're located in the UK - is the house on the older side? I used to live in Chicago and lived in a place where the electrical wiring was probably 50 years old, so it did some pretty funny stuff. Really the only way to get around that kind of problem would be to get a good quality surge protector or a UPS and see what happens.

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Answer 6

cfane Author

Level 1

8 points

Jun 19, 2008 1:53 PM in response to the jackamo

that would have surprised me i nthe last place i was in, the house was a 150 years old, and im not sure when the electrics were last replaced, but this place is only about 15 years old. Ive only had problems in the newer house, and my mac book pros plugged in the adjacent socket without any issues.

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Answer 7

AndyO

Level 6

17,064 points

Jun 19, 2008 2:05 PM in response to cfane

Even if in a 150 year old house (in the UK), unless the sockets are round pin (15 amp) it will have been fully re-wired at some point (usually early 1960s) to bring it up to 13 amp square pin standard. Of course wiring deteriorates over time, so even since (or with the newer property) it's possible to have a wiring issue that causes problems. In that instance you'd expect to see failures with other equipment too of course, though not usually laptops.

Have you got a device for checking the wiring is correct - that it is not reversed for example between live and neutral or that the ground is correctly at zero and not suffering floating voltage? Such things can be obtained from most electrical stores, Maplins, and probably even the right aisle in Tescos and the like.

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Answer 8

Jun 19, 2008 4:06 PM in response to cfane

Hi,

So, the only thing that time that it worked after the first failure is when you used the other power adapter that you borrowed from your friend? That's odd.

Have you tried turning the power adapter 180 degrees around?

I'm not sure of the pinouts on the power adapter. Do you have a voltage tester? You could see if there was power coming to the computer.

Do you have an Apple service center nearby? They may have more test equipment.

David

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Answer 9

cfane Author

Level 1

8 points

Jun 19, 2008 4:17 PM in response to David Dellinger

After the first failure, i got the mini working again with my friends power supply. so i assumed it was the power supply, and spent the money for a new one. i plugged in the new one, and everything was fine for an hour and half. after which i needed to move it into the other room to its usual desk. After this exactly the same happened as before, plugged in the power, and nothing happened, no light etc.

ive tried the power lead up each way. Ive probed the output of the supply, and i assume its got some sort of protection system on it, so its got to be connected to function, as i got voltages of -0.2v or something.

I had thought it might be something loose, causing it to fail after being moved; so i even tried the rather un-scientific method of shaking it, then trying to power it on. Ive opened it up, and cant see anything visibly wrong on the logic board.

Unfortunately my nearest centre is about 60 miles away, so i think its looking more and more like it will end up being sold off as parts.

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Answer 10

AndyO

Level 6

17,064 points

Jun 20, 2008 3:58 AM in response to cfane

I assumed you would have checked, but over here in the US most users wouldn't have been aware there are fuses in UK mains plugs, so I thought I'd better ask!

If the nearest Apple store is too far away, it might be worth contacting your nearest Apple Approved Service provider and asking if they can diagnose this problem for you - some will do this at no cost.

It does seem important however to check the wiring in your house to ensure each socket is wired correctly. It may be coincidental that both times it has failed it has done so in the same place, but it could indicate there is a fault in the cabling which could be causing it.

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Answer 11

AndyO

Level 6

17,064 points

Jun 18, 2008 1:29 PM in response to cfane

The battery is worth changing yes, and while I don't recall a note that a failed battery would prevent power-up, it would not be the first mac that suffered that fate!

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Answer 12

cfane Author

Level 1

8 points

Jun 18, 2008 1:32 PM in response to AndyO

Thanks, Ill give that a go.

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Answer 13

cfane Author

Level 1

8 points

Jun 18, 2008 1:45 PM in response to cfane

Unfortunately a new PRAM battery hasn't helped 😟

hmmm...

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Answer 14

Jun 19, 2008 1:13 PM in response to cfane

Are you using a surge protector or just plugging it straight into the wall?

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Answer 15

cfane Author

Level 1

8 points

Jun 19, 2008 1:19 PM in response to the jackamo

Its been on one for most of its life. Ive tried different outlets in different parts of the house, with and without surge protectors, and it doesnt seem to have made any difference.

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