am i supposed to be using both connectors on the nexus?

andyd · Post by **andyd** » Sat Jul 09, 2005 4:26 pm

or is using the 3 pin one enough?

mathias · Post by **mathias** » Sat Jul 09, 2005 4:29 pm

If the 3 pin connector has a middle (red) wire then no. If it doesn't then you can, it's just for RPM monitoring.

andyd · Post by **andyd** » Sat Jul 09, 2005 4:36 pm

kk cool...good info to know

Michael Sandstrom · Post by **Michael Sandstrom** » Sat Jul 09, 2005 4:41 pm

I think on the Nexus both connectors are for power and only one should be used.

Post by **Rusty075** » Sat Jul 09, 2005 5:03 pm

Yes, use one, or the other, but never both.

andyd · Post by **andyd** » Sat Jul 09, 2005 5:43 pm

ok...using just the 3 pin connector. an issue though...

the bios keeps showing that the rpm drops to 0 and speeds up again but i dont see anything wrong with the way the nexus is spinning. i had to turn off the rpm warning in order to get things going. is this normal behavior?

Michael Sandstrom · Post by **Michael Sandstrom** » Sat Jul 09, 2005 7:17 pm

I have both of my Nexus fans undervolted and the only program that correctly shows low fan speeds on my system is the great free system info utility Everest Home Edition.

ONEshot · Post by **ONEshot** » Sat Jul 09, 2005 7:25 pm

I plugged in both, I have had no trouble... But I'll unplug one if this is doing something wrong...

mathias · Post by **mathias** » Sat Jul 09, 2005 10:50 pm

Michael Sandstrom wrote:I think on the Nexus both connectors are for power and only one should be used.

My 12cm nexus was missing the power connector on the 3 pin connoctor. Some have a 3 pin power connector, some have an rpm monitoring only 3 pin connector.

And even if it does have a power connector, you could cut it if you want to power it of the molex and have rpm monitoring.

m0002a · Post by **m0002a** » Sat Jul 09, 2005 11:22 pm

ONEshot wrote:I plugged in both, I have had no trouble... But I'll unplug one if this is doing something wrong...

You should not use both the 3-pin and the Molex connectors. I am surprised your PSU has not blown up yet.

nick705 · Post by **nick705** » Sun Jul 10, 2005 1:15 am

m0002a wrote: You should not use both the 3-pin and the Molex connectors. I am surprised your PSU has not blown up yet.

I don't think it's quite that simple, as there appears to be more than one version of the Nexus fan around and Nexus's product info page isn't very helpful.

There's another thread here asking the same question...

darthan · Post by **darthan** » Sun Jul 10, 2005 1:36 am

Actually, it really shouldn't matter whether you use one or both unless your motherboard (where I assume your three pin fan headers are) has a fan speed controller. If it doesn't then plugging the fan into both just means it is connected to the 12V line of your PSU through two different wires and to the ground through two wires but the circuit is still basically the same. However, if your motherboard has a fan speed controller, and especially if you turn it on, then it will reduce the voltage through the three pin header and you will get current flowing backwards into your motherboard from the 12V line to the fan controller on your mobo. This is exactly the same problem that the 7 volting trick has except that your PSU almost certainly has some amount of draw on the 5V line such that nothing will burn out while a mobo fan controller is quite likely to fry if current runs backwards through it. So, it isn't a hard and fast rule as to whether or not it will be a problem to plug in both connectors (if the three pin connector has the red and black power wires) but it is always better to be safe than sorry.

kesv · Post by **kesv** » Sun Jul 10, 2005 2:22 am

andyd wrote:the bios keeps showing that the rpm drops to 0 and speeds up again but i dont see anything wrong with the way the nexus is spinning. i had to turn off the rpm warning in order to get things going. is this normal behavior?

Some bioses have trouble interpreting the rpm signal from low spinning fans. There are some monitoring softwares around that do a better job.