The 2013 revamp of the desktop Mac series known as the Mac Pro.

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Mac Pro 2013 is not powering on (lights On , Fan Off , No Chime )

Hi, to make this short as possible

Note I also posted is also on another site and I’m gonna include everything with yesterday’s updates at the end.

I replaced the GPU on my Mac Pro 2013 and while doing that I replaced the thermal paste for the CPU too now the computer is not powering on ( No POST ) I have the lights on except the power button light is off .. first I thought it's something with the new refurbished GPU but it's not because I tested it with another working GPU.

After searching the net people are saying it might be :

  • The battery inside needs a replacement ( I did a replacement with no luck. )
  • The power supply is not working ( I can see the red light after hocking up the power cable ( Without the logic board installed if the logic board is connected to the riser the red lights in the logic board and the PSU will go off as normal behavior ) I also get the green light when I press the little check button on the I/O board from the inside ( more details about this at the end ) then I used the multimeter to measure the power that it's going to the CPU riser and it's giving me 1V .. I don't know if it's the right number.
  • The logic board got damaged? but why? everything is fine also it's red light is on when it's connected to the PSU only .. it's not my first time disassembling the Trash Can and I did it so many times and I even looked at the sensitive data cables that connect the logic board to everything I can't see any broken pins.
  • Someone said press shift on the keyboard while turning on the device but I’m using a USB keyboard and there is no power on the USB ports ! the screen wakes up though pressing the power button (connected via thunderbolt )

Finally, I always take precautions like wearing an anti-static bracelet and not using any screwdrivers with magnets also changed the power cable connected it directly to the wall

Please help .. Thanks

TL,DR : I/O lights On except the power button No Chime No Fan Just the Lights for 15 sec then they go off .. PSU seems fine ( I might be wrong ) .. I put the older GPU back, replaced the battery with no luck.


I followed this guide ++,1_...

I got #2 & #5 on while the computer is off .. will try to do power on without the lid I just need a magnet that I don't think that I actually have at the moment

UPDATE #2: I managed to find a magnet and activate the computer power without the cover being on ( if you wanna do it too just stick the magnet next to the power button outside the seam. )

Now thankfully I got all the Diagnostic LEDs on Green Light Except the first one which means everything is working !!!!! then why it's not POSTING !!!!?????

Also, does anyone knows how to check the CPU Riser LEDs without dismantling the whole thing and make everything dangling with a magnet stuck to the I/O it’s seems a little bit dangerous to do that?

UPDATE 3 : I just noticed that Error LEDs ( two RED ) on the logic board are on ! ... Still don't know what that supposed to mean.

Please help

Thank you

crwdns2893858:0crwdne2893858:0 crwdns2893862:0crwdne2893862:0


crwdns2889612:0crwdne2889612:0 2


Hi, I have the same problem just #2 and #5 lights up, what did you do to let the all indicators light to turn on?



Sorry I don't remember, I followed the service manual .. you can find it on eBay as PDF file


@Yair Sabag

When you have the housing off, you have to hold a magnet close to the power button, to make all the leds light up.


WOW, I'm still getting comments on this after those years!

Well After I got that GPU I didn't want to pay more for a logic board ..

I moved the CPU/RAMS/SSD to PC build and it's working since then .. Actually I added anoth CPU and now I have dual CPU PC with 2080ti

This MAC Pro is a scam cause apple knew the issue before the release

it's sitting now as a design piece decoration on my shelf.


Thanks for that, but I meant the indicator led light on the board..@vocamacrepair





Logic Board Error LEDs

CPU Check: This indicates that there is a connection issue between the logic board and the CPU riser card. Verify that

the edge connector on the CPU riser card is fully seated into the slot on the logic board.

GFXA Check: This indicates that there is a connection issue between the logic board and Graphics Board A. Check

the mezzanine connectors on both the logic board and graphics board to be sure the connections are fully seated.

GFXB Check: This indicates that there is a connection issue between the logic board and Graphics Board B. Check

the mezzanine connectors on both the logic board and graphics board to be sure the connections are fully seated.


crwdns2889612:0crwdne2889612:0 1

Similar problem. In my case, the red light was coming from the bottom of the unit, the logic board. I replaced the logic board and was back in business. Turns out, it had been dropped. Dent on the bottom and the riser stand-off screws holding the logic board in place were broken.


crwdns2889612:0crwdne2889612:0 0

Hello, my Mac Pro had the same symptoms, except that in mine the fan could be heard if you put your ear too close.

I thought it was the graphics card why it didn't give video and turned on, but I took it to an Apple Premium Reseller for a diagnosis and he told me that the CPU Riser Card had to be changed.

I think it must have overheated the CPU because the fan had started to fail me some time before I had unexpected reboots.

Before stopping giving video I had unexpected restarts, then it turned on randomly and finally it no longer gave a video signal.


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