I had to replace a damaged case/cpu-fan in a Dell 8400 System. The fan Dell sent me was a "Nidec BETA V TA 350DC, 12V 2.3A".
I noticed that the fan had a 4-Pin Mainboard Adaptor (Dell 925X Board). 1 white wire (named MX), 1 red wire (named 7D), 1 black wire and a blue one. So far I have only seen 3-Pin Board Connectors.
Could anyone please help me to understand the idea behind this? What are the four pins good for? Just curious.