Chosen Solution
This machine has not been used much. It was purchased in 2011, and has been idle for about a year. No light appears at the front where I push the start / on buttonNo internal sounds are evidentI replaced the BR2032 with a CR2032 and no different outcome when I push on buttonNot much dust insideI removed the graphics card and re-seated. Did the same with CLU shelf and disks.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)
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)
The upload tool is a bit funky.
Still funky… The point with pics is that there is virtually no dust.
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.
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).
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.
I’m having the same issue as stated above… diagnostic LEDs say backplane and PSU are okay but machine won’t boot or jump start (with all hardware stripped out… processor cage, graphics card etc). Even stranger thing is that I’ve replaced the back plane and swapped the PSU with another of my machines but still the same result!? Obviously something is wrong but it’s impossible to say exactly what…
My Mac Pro 5.1 has the same situation. Who has solved the problem please share
Having the same problem. Mac Pro 2012 (2 x 6 core). During storms in Sydney a week ago we had a power surge. TV acted strangely for a while the next day but eventually recovered. Thought nothing more about it. A few days later Mac Pro started to refuse to wake from sleep state (breathing LED). Then yesterday refused to power on. No front white LED, no clicks, chimes, fans internal LEDs - nada! Seems utterly dead. However, pushing the diagnostic button on the backplane near the Front USB card causes one orange LED to appear. Seems like the consensus is one of two solutions - new motherboard or new power supply. Both are big $$$, so any further thoughts would be appreciated!
