Bad power supply?

[heisenburg]

My 2008 Mac Pro refuses to power on, when I push the power button nothing happens.No lights or fans power on; it acts like it is unplugged, but it is not unplugged. I tested the power cord in an another machine, and it worked fine. At this point, I'm thinking I will need to replace the power supply. Has anyone else had this issue?

[Macsonic]

Originally Posted by heisenburg

My 2008 Mac Pro refuses to power on, when I push the power button nothing happens.No lights or fans power on; it acts like it is unplugged, but it is not unplugged. I tested the power cord in an another machine, and it worked fine. At this point, I'm thinking I will need to replace the power supply. Has anyone else had this issue?

Try using a different power cord or plugging your Mac Pro to a different outlet. If nothing happens it may be likely your power supply. Is your Mac Pro plugged to a UPS with surge protector or plugged directly to the wall outlet when you are using this?

[bsbeamer]

Originally Posted by heisenburg

My 2008 Mac Pro refuses to power on, when I push the power button nothing happens.No lights or fans power on; it acts like it is unplugged, but it is not unplugged. I tested the power cord in an another machine, and it worked fine. At this point, I'm thinking I will need to replace the power supply. Has anyone else had this issue?

Try unplugging EVERYTHING from the machine (all USB, monitors, ethernet, etc.) then plug power cord directly into a tested & working outlet. If the machine doesn't power on at that point, then it's probably the PSU. Can try unseating all PCI cards as well, but that's only caused a power issue for me once on a PC many years ago.

If replacing PSU yourself, be sure to get the right part number, they're all a little different...

[heisenburg]

Originally Posted by bsbeamer

Try unplugging EVERYTHING from the machine (all USB, monitors, ethernet, etc.) then plug power cord directly into a tested & working outlet. If the machine doesn't power on at that point, then it's probably the PSU. Can try unseating all PCI cards as well, but that's only caused a power issue for me once on a PC many years ago.

If replacing PSU yourself, be sure to get the right part number, they're all a little different...

I just removed the power supply from my Mac Pro. I then opened the power supply (yes I know there are 450v capacitors). I then tested the fuse which was not blown. I noticed that there was scorch marks on the metal inside the power supply. Does this just happen over time from high temperatures, or did my power supply have a melt down?

[MacVidCards]

Make sure you do a SMC reset. Just means yanking the plug and then holding power button down for 5 seconds or so. Plug in again and hit power. Listen for click

[heisenburg]

I see burn marks inside the power supply, so I assume, the power supply died. Do I have to get the exact same part number? The part number on my power supply happens to be the most expensive Mac Pro power supply there is. I see other Mac Pro power supplies with the same wattage and same power connectors, but they have a different part number. Will they be ok for me to use?

[666sheep]

You need 661-4677 (614-0409). These with different part numbers have different (lower) amperage on 12V lines. There is used one for $140 on US eBay ATM.