HP Compaq 6000 SFF Any Power Supply Loud

Hello,

I'm currently at a school district that uses HP Compaq 6000 SFF Desktops.  A user said that their power supply fan sounds like a rocket engine.  I have spare parts here and have tried about 4 different PSUs and they all do the same when I boot up; the power supply sounds like a jet engine.

I have unplugged and reset everything on the computer (RAM, HDD, Drives, everything) and I get the same result. The jet engine sound.

Any ideas of what it could be?  Could it be the motherboard?

Thanks for any responses.