Strange (click) sound on power off/hibernate!?!

[Xanix]

Hello to all. Recently, I purchased a 2nd hand 2010' Mac Pro. It is in a perfect working order and good cosmetic condition.
Wath I found strange is, when powering off or hibernating, it makes a strange (click) sound! Is it normal?
I'm asking this, because, I'm used to work with macbooks and iMacs; no Mac Pros.
Is it the psu, the hard drive, the dvd reader?

Thank's and regards,

Xanix

 

[nanofrog]

There are relays in the PSU (one on the mains, and another on the power switch).

Given your description (no mention of problems during startup or resume from hibernation), the click you're hearing is normal.

 

[odinsride]

Don't sweat it, it's normal