Should I use both the small MB connector AND the big 4 pin?

New to PC silencing? Read & post your questions here. Dedicated to rosy_toes.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
scottfa
Posts: 15
Joined: Mon Aug 20, 2007 7:16 am

Should I use both the small MB connector AND the big 4 pin?

Post by scottfa » Mon Aug 20, 2007 7:22 am

A noobe question for sure!
I purchased the Ninja Plus and hooked up the fan using both provided connectors. Intermittently the fan will not start rotating upon power up. If I give it a little push it will rotate. I have the feeling that I should just use small connector to the motherboard.....
Thanks!

BillyBuerger
Patron of SPCR
Posts: 852
Joined: Fri Dec 27, 2002 1:49 pm
Location: Somerset, WI - USA
Contact:

Post by BillyBuerger » Mon Aug 20, 2007 9:12 am

First, disconnect one or the other immediately! The two connectors are there as an either or situation. Either use the 4-pin molex to power directly from the PSU and therefore run it at it's full 12V. Or, use the 3-pin fan header to plug into your motherboard. If your motherboard supports any kind of fan speed controller, then it could run at low-rpms when things are cool.

Now, if your motherboard does not support and fan speed controller, then the output to the fan should be the same 12V that it would get from the PSU and having both connected shouldn't cause any problems. (I still would not do it though) If on the other hand, your motherboard does support a fan speed controller, it would be supplying less than 12V to your fan, but your fan is also connected directly to the 12V rail from the PSU. Meaning that it would probably be sending current back into the motherboard through the fan connector. VERY BAD!

If the fan isn't spinning right away when connected to the 3-pin motherboard connector, it could be that the CPU is running cool enough that the fan controller is sending a low enough voltage to the fan that it won't start. Not really a big deal. As the CPU gets warmer, the voltage will increase and the fan will start spinning. Most likely, it will have enough inertial by that time and won't stop even if the CPU cools back down.

scottfa
Posts: 15
Joined: Mon Aug 20, 2007 7:16 am

Post by scottfa » Wed Aug 22, 2007 11:46 am

edit: you answered my question....thanks

Post Reply