The Mac Pro First Generation is an Intel Xeon-based workstation computer manufactured by Apple Inc. The first generation model includes the machines from 2006 through 2008.

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MacPro does not power on... and does not attempt to boot

This machine has not been used much. It was purchased in 2011, and has been idle for about a year.

  1. No light appears at the front where I push the start / on button
  2. No internal sounds are evident
  3. I replaced the BR2032 with a CR2032 and no different outcome when I push on button
  4. Not much dust inside
  5. I removed the graphics card and re-seated. Did the same with CLU shelf and disks.
  6. A red light flashes, if I attempt to plug in while CPU shelf is out, so there is power to the mother board

It was working fine when I shut it down a year ago.

Any ideas?

Thanks, John

Update (01/24/2016)

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Hi Jim,

The pics are a bit dull. This pic should show that memory slots 1-4 have 1GB stick, slot 5 has 4 GB and slots 7-8 have 1 GB sticks.

I believe that this is way it came. Above, I indicated that my son my have borrowed some memory but I was wrong.

:-)

Thanks for your interest,

Max

Update (01/27/2016)

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The upload tool is a bit funky.

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Still funky... The point with pics is that there is virtually no dust.

Answer this question I have this problem too

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Are any of the internal diagnostic LEDs on?

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Hi Mayer,

Excellent question... I finally found the Apple tech guide here:

URL = http://tim.id.au/laptops/apple/macpro/ma...

And the advise in the Diagnostic section asked the same question you have.

I will get to this tomorrow in Toronto time... and then re-port my findings.

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The MacPro machine is an 8-core... I have been looking at the memory...

There are four sticks of 1 GB each on the right most memory bay slots 0-3

While there are three (3) sticks of 4GB in the left most bay in slots 4-6.

I have a sense that my son liberated one stick of 4 GB.

So I pulled the 1 GB stick from slot 3 in what I think is in accordance with the Guide,

But it made no difference.

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I appreciate your response,

Max

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When attempting to diagnose this machine, always take it back to the original configuration first, that includes any added PCI cards, Added RAM and added hard drives. Also knowing the exact machine is helpful.

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Ok, so I did the diagnostic tests and the first failure observed was re: Page 35, wherein the Apple Guide asks me to 'momentarily jumper' the SYS_PWR pads on the motherboard.

I did this by itself and then while holding down the Diag button.

The expected results from Apple Guide was the fans should turn slowly... etc...

My results were nothing happened.

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I also reset the RTC via the button next to the battery BR2032.

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Lastly, when plugging the power cable in, both Red lights entitled OVTMP CPU A and B flash momentarily red, which seems to be good.

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Curiously, Apple does not offer advise for the SYS_PWR diagnostic when it fails.

Any ideas or observations would be helpful,

Max

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Would you go here and input your serial number so we know your exact machine: http://www.everymac.com/ultimate-mac-loo...

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3 Answers

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The two main failures on this model are first the video card, then the power supply. The power supply is sneaky as it will partially fail. It usually begins with unexplained reboots. This may only happen once or twice a week. However as time goes by the frequency of the reboots increases until you just can't stand it anymore as it's doing it 5-9 times a day. On the 6 machines I've worked on, all responded well when the supply got replaced.

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Hi @mayer!

I have the same problem here, the only LEDs that illuminates when pressing the DiagLed button is 5v STBY, when plugging the power cable 2 leds illuminate on red: OVTMP CPUA/OVTMP CPUB, when unplugging the power cable one led illuminates on red, this is the same according to the manual.

But I don't want to swap the logic board/backplane, until i'm sure in 100%, that the problem did not came from the power supply.

Now, logically, if i'm understanding well, STBY means: the power is going to the backplane, but the backplane aren't receiving enough power, to properly power on the Mac, and then the logic board are in standby mode waiting for the enough power to come.

Now, i'm waiting a friend to come with the Mac Pro that he own, to make a test with the working power supply, if mine power on with it then i'll buy one if no, then i'll go for the backplane.

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Mohamed My answer hasn't changed. Let's wait and see what the new power supply does.

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Please @mayer!

The friend of mine will not come until this week-end and maybe not, I don't want to be in the STBY too. So i have to buy the PSU in this coming three days.

And before i buy the power supply, i just want to make sure, that i've forgot to mention on the last comment, that i own a 2009 Mac Pro 4.1.

So, would the power supply solve it's problem?

I'm waiting please for your answer to click on that purchase button on eBay!

Thanks

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I just want to add, that, if i jumper the SYS_PWR by a copper cable, the fans won't spin.

Could it be here once again the power supply?

Please @mayer !

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It didn’t solve that problem, still the motherboard shows the same thing with the new PSU! So it’s the backplane now, i’m going to change it, but after getting it’s budget!

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I'd treat it as a standard NPNV (no post no video) and strip it of all non-essential POST hardware, including all accessory cards and all RAM beyond the minimum POST requirement. After that, swap the RAM sticks and see if it will post with each different pair. Also try using non-standard RAM slots if the initial slots don't work (it could be a dead channel).

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Worst case if it's a dual proc board is you pull one of the procs, and try the NPNV rotation with each processor individually. The goal is to rotate the minimum hardware spec until you can determine which part is failed.

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Thanks for the suggestion...

I will do a bit of reading and try your suggestion.

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Did you have any luck with this? I have a Mac Pro 4,1 (single CPU) that is exhibiting the same symptoms. It was on 2 days ago, now no power on at all.

UPDATE 07/12/2017

Hi Max Entropy! Thanks for the quick and detailed reply. (I'll stick to replying to this thread, instead of starting new answers...)

I, too, have a second working machine, but I've yet to start the process of swapping components. My hunch is the same as yours — a surge has damaged the power system on the backplane board. The diagnostic button shows 5V on the backplane board, but jumping the SYS_PWR jumpers has no effect, which is all the detail that the Apple technician guide goes into.

So, I don't have any questions right now, but I would be very interested to hear how your new power chip works out.

Thanks again.

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Steve check your email...and then iFixit... For my reply below

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Hi again! Any luck with this? Hope your Mac Pro is back to life...

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Hi @Steve

Did your Mac Pro 2009 worked by, changing the logic board? because I have the same symptoms as your Mac!

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Hi @ammoune78

I didn't do a full logic board swap, but swapping processor trays from a known-good Mac Pro 4,1 resulted in:

- Problem Mac Pro: no boot with working CPU tray

- Working Mac Pro: no boot with suspect CPU tray

I concluded that more than just the logic board was damaged — signs point towards both the logic board and CPU tray... :(

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Hi @Steve

This is really sad, this could be the surge in the motherboard, that affect all other components! But the suspected CPU tray, was originally took from the working Mac, or the original that came with the faulty Mac?

For me:

I moved the Mac to an technicien, to see if he can repair the power supply. He reported to me that, every time he change its transistor, the PSU become again faulty, and same thing if he change another time that transistor.

But the strange thing is, when i plug the power cable, 2 leds illuminate on red: OVTMP CPUA/OVTMP CPUB, when i unplug the power cable one led illuminate on red! This as Apple said, confirm that the BackPlane isn't faulty.

IMHO, I suspect that the power supply must be totally replaced not the components, because it's the power supply that allow or block the surge and the short-circuit, and it should be replaced but not repaired.

Because if you continu, swapping or buying other components such as, the backplane cpu tray, i think they will have the same problem. See if there's humidity in the case!

An example here, but from PC not Macs, my sister home had a very big surge, that occurred 2 years ago, 80% of the electronic things died, except TV's and Refrigerators and only one computer survived. This one had Corsair 650TX PSU, while another computer completely died, from the PSU to the CPU. And the one with that Corsair PSU still work, even if the motherboard was made for the 1 generation Intel i series CPUs, the PSU and the GPU now makes a small sound, like the bad electrical sound, but they still work, with no problem. I'm sure, that the PC with Corsair PSU, should be died without it!

This is just my opinion.

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Max Entropy will be eternally grateful.
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