Mac Pro 3,1 Random Shutdowns

[VaZ]

A buddy of mine brought his MP3,1 over to show me how it randomly shuts down as if the power cord goes unplugged.
It feels like it's getting worse and has trouble making it to the desktop now.
Trying with multiple boot drives Lion, El Capitan, High Sierra, Mojave, Windows 7 and 10. Same result shuts down randomly with no apparent pattern. Sometimes it makes it to the desktop with each but then power cuts out.

Any help will be greatly appreciated !

 

[tsialex]

A buddy of mine brought his MP3,1 over to show me how it randomly shuts down as if the power cord goes unplugged.
It feels like it's getting worse and has trouble making it to the desktop now.
Trying with multiple boot drives Lion, El Capitan, High Sierra, Mojave, Windows 7 and 10. Same result shuts down randomly with no apparent pattern. Sometimes it makes it to the desktop with each but then power cuts out.

Any help will be greatly appreciated !

Check the main logic board if have any signs of corrosion. I have 2 early-2008 corroded MLBs heres with the exact same problem that you describe, sometimes even work for half an hour. Other thing to check, if no corrosion, is the PSU.