Early 2008 Mac Pro PSU

[supercooled]

Hi, I've been wondering about this for some time now but never took the time to ask. Why is it when the machine powers down, there is a very noticeable click from the power supply? This happens when it shuts down or goes to sleep mode. Before the Mac Pro, I've always built my own system and none of the OEM PSUs ever did this.

Curious yours,

 

[Infrared]

Hi, I've been wondering about this for some time now but never took the time to ask. Why is it when the machine powers down, there is a very noticeable click from the power supply? This happens when it shuts down or goes to sleep mode. Before the Mac Pro, I've always built my own system and none of the OEM PSUs ever did this.

Curious yours,

http://en.wikipedia.org/wiki/Relay ?

 

[nanofrog]

http://en.wikipedia.org/wiki/Relay ?

That's exactly what it is, and they are needed in large PSU's.

 

[supercooled]

Thanks guys. Just to expand on my original curiosity; I'm assuming Apple has been using high capacity PSUs since the Power Mac days, so how has reliability been? My 12 months is coming up and I'm honestly thinking about foregoing the AppleCare extension but the PSU is the only wild card.