CPU fan third wire

[orange]

I noticed there are three pins on board for fan in this card:
http://www.amiga-hardware.com/download_photos/gvpgforce040_2_big.jpg

is third pin unused? can I safely connect modern fan with its third, yellow, wire?
or should it be cut?

[Daedalus]

Yes, that third wire on modern fans is feedback to the motherboard of the speed - it gives a pulse every revolution of the fan which is where modern machines get their information from in CPU monitoring applications etc. Cutting it won't make a difference, and anyway I don't know of any Amiga software to make use of the feedback. Classics certainly can't without a bunch of additional hardware...

[gertsy]

I noticed there are three pins on board for fan in this card:
http://www.amiga-hardware.com/download_photos/gvpgforce040_2_big.jpg

is third pin unused? can I safely connect modern fan with its third, yellow, wire?
or should it be cut?

Never! cut the yellow wire!  It's always the red one!...  Or is it the blue one....?

Chick, chick, BOOM!

But seriously that looks just like my GVP040.  I replaced the original with the same type of bronze coloured aluminium heatsink and slimline fan.  Freaky...  
I don't think there is a speed signal on these cards.  I'd remove it, if the fan operates without it.

[mongo]

I noticed there are three pins on board for fan in this card:
http://www.amiga-hardware.com/download_photos/gvpgforce040_2_big.jpg

is third pin unused? can I safely connect modern fan with its third, yellow, wire?
or should it be cut?

I would cut it because you don't need it and I don't know what it's connected to on the board.

[Ilwrath]

Yeah, 3rd wire on a fan is a pulse.  (Used to measure fan speed on newer hardware).  I agree with everyone else.  Cut it and leave it disconnected like the original.  Who knows what that 3rd pin is actually connected to on the GVP...  (I don't think they commonly used pulse back then.)