Chosen Solution

Update: First, sorry for the hiatus. I’ve been out of the business for a while. But I’m back! Apple couldn’t tell me anything. They offered me to pay a flat $500 fee, and they would replace anything that needed to be replaced untill it worked… I ended up just selling it for parts… So I have a Apple Mac Pro “Quad Core” 3.7 (Late 2013) that wont power on. I do not know the history of the machine. I plugged it in and got nothing, no beeps. no fan spinning, no response. I do all the normal procedures, swapped ram, tried different SSD, reset SMC, tried different power cable and outlet. None of that worked. I took the case off and found a bright red LED shinning.

So I started searching the internet, thinking that there MUST be some information about this red LED…. NOTHING!!! So I proceeded to take the whole thing apart, took it down to bare bones to make sure everything was connected properly and to see if I could find any corrosion from any liquid damage or such. While I was at it I re applied thermal paste on both the CPU and GPU. Nothing appeared to be out of place, no damage to the board, all connections were secure. I put it back together, powered it on, and still nothing, just the red LED… WHAT IS WRONG WITH THIS THING!? Please, if you have any idea what could be wrong, any suggestions, or any explanation about this red LED I would LOVE to hear it. I’m totally baffled by this one… Thanks in advanced, Taylor

Hi! Did you solve it? I have the same problem. Best regards Petter

Any luck? Was just handed a mac pro with exact same problem. This was after upgrading CPU.. only a red led on psu board lights when power cord plugged in and another red LED on the bottom (round) logic board. pressing power gives no life of any kind.