Mac Pro 2012 tower does not turn on

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Level 1

8 points

Mac Pro 2012 tower does not turn on

Hello, everyone. I have a Mac Pro 2012 5.1 12-core at my company that is being used as an editing suite. Last week it suddenly shutdown while working and would not turn on anymore. I left the power cord unplugged through the night and plugged it back the next morning. It did turn on. When I got back that afternoon, it was off and now it won't turn on anymore. When I plug the power cord the red light flashes on the front. When I press the diagnostics leds the amber light turns on 5V STBY. I did a bit of research on the web and found that this is just an indicator of trickle power being fed to the computer.

Does anyone know if there is anything I can try before sending it to maintenance? I think that maybe there might be something wrong with the on switch, but the wire goes down behind the processor board dock and I can't see or reach with my fingers in there.

Cheers!

Mac Pro, OS X Yosemite (10.10.5)

Posted on Feb 7, 2017 9:17 AM

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Answer 1

K Shaffer

Level 8

35,314 points

Feb 7, 2017 10:43 AM in response to rmduarte

One item that may affect the ability for the Mac Pro tower (and predecessor PowerMac G5, etc)

would be a good condition clock battery; if never replaced and if left unplugged for a time, this

could contribute to startup issues: If Mac Pro5.1... Backup Battery 3V CR2032 Lithium.

There may be other items of consideration, such as power supply, capacitors, and even such

effects as what else may be sharing the circuit where the Mac Pro tower gets its power. If you

have a UPS backup power supply (automatic switching, power conditioning) that could filter

some irregularities; such as a freezer turning on -- that may cause the Mac to shut down, etc.

You may choose to read through the iFixit guide to see if anything there may help,

as troubleshooting is an important factor in keeping a power computer functional.

Here is a link to the Mac Pro 2006-2013 troubleshooting page

The iFixit guides page seems to show 'first edition' mostly:

https://www.ifixit.com/Device/Mac_Pro_First_Generation

Did you try an NVRAM reset?

How to reset NVRAM on your Mac - Apple Support

For other power-related symptoms, you might need to try reset the SMC instead.

Not sure if anything I've mentioned would help all that much...

Good luck & happy trails! 🙂

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Answer 2

Feb 7, 2017 10:48 AM in response to rmduarte

I had something similar happen to a 2010 6 core 5,1 Mac Pro. One key similarity is that it would start after being unplugged for a while. Apple initially diagnosed it as a weak button battery, but after working on it, determined that the power supply was going too. Replacing both fixed it.

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