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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Mac Pro 5,1 won't boot. No power, no noise at all, only a couple LEDs.

HI there,

I have a customer's Mac Pro, mid 2012 machine which won't boot at all. When I press the power button, nothing happens at all, except a light odor of the magic smoke (from electronics, that is). The only time something noticeable happens is when you are looking at the logic board while plugging in the power cord. What I see are the top two LEDs that blink red momentarily in the upper left corner, below the #1 HDD. Those lights go out almost immediately and do not illuminate again when pressing the power button. I can get the lights to stay on if I depress the power button while plugging the machine in and hold the button in for about 7-10 seconds. They will stay on permanently after that.

When I press the Diag button near the LEDs, the 4th LED lights up amber, but nothing else notable happens. This also happens if I have the red lights switched on as I mentioned above. I tried the SMC button, but that didn't do anything either. Nothing at all in either case.

The customer already replaced the power supply, so I am wondering if the logic board is bad. I am going to get another power supply to be sure, but what else could it be??? Is there some other board I don't know about? Can someone help me interpret the LEDs?



Answered! View the answer I have this problem too

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Thanks for the help, but after I posted that I did a little more digging. Turns out that the video card tries to power up when the machine gets plugged in, and every time I plugged it in, I let a little more of the magic smoke out. I used my eyes to trace where the smoke was coming from, and sure enough I found some blown ICs on the graphics card. Put another card in and viola! IT WORKS!!!! Something in the short circuit on the GPU card must have been dragging the power supply down or something…

Thanks for the help, but it was not the power supply! What an odd one!

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Failed video cards are the #1 issue I've seen on the 2008-2012 MacPros. I've lost two myself.


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It sounds like you need a power supply. I doubt jumping the solder pads on the board will make a difference for you because it's doing the same job as the power button, but in a different spot on the board.

It may also be the Backplane board, but I can't see a way to figure it out without test parts.

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Mac Daddy will be eternally grateful.
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