[Bob in St. Louis]

The 40x40x10 cooling fan in my double bay RAID drive locked up (no telling how long ago  ). I bought a fancy new, ultra quiet replacement model and ran into a bit of a snag. Well, two snags.

First, the new fan is three wires, the old is two. I have no problem (no fear) cutting the old PCB plug off the old jack and soldering it on the new fan. But...I know DC could be wired either way, it'll just make the fan spin the other direction. So, how do I know which two wires to use? Does it really make a difference, or is it just a matter of getting voltage to the motor in the correct polarity? Process of elimination?
I hate the idea of sticking them on the "hot" board and..... "testing" which wires in which polarity.

Second, I assume the safest bet would be for the fan to pull hot air out out of the case as opposed to stuffing cool air in?

Thanks folks. Will be nice to have tunes again. I've been without for a few days.
Bob

Here's a photo of the fans and circuit board.

[Levi]

Three wires on the newer fans means it can be controlled (speed).  The three pins are used for ground, +12 V power, and a tachometer signal.  You can easily splice it and turn it into 2 wires (plus) and (minus).  Since it is not color coded, you may have to refer back to the fan manufacturer.  You may have to strip it and do a trial by error.

If the fan is in the back of the unit, more than likely it is an exhaust.  So, it should pull (suck) hot air out of the chassis.

[Bob in St. Louis]

  The soldering station is warming. Thank you Levi!!
Tunes soon! 

Bob

[Levi]

You are welcome!  glad I can help.

[Bob in St. Louis]

The tunes are spinning, and the air is flowing. Thanks!!

Bob

p.s. I used Cardas Silver Solder, just in case it matters.   

[Levi]

p.s. I used Cardas Silver Solder, just in case it matters.   

The silver solder will surely last a long time. 

[Dan Banquer]

I'm sure the silver solder will make the fan sound so much better too.
d.b.

[jtwrace]

The tunes are spinning, and the air is flowing. Thanks!!

Bob

p.s. I used Cardas Silver Solder, just in case it matters.   

Is it much quieter?  Which fan did you use?

[Bob in St. Louis]

Oh yea.....the new fan with Cardas Silver soder is soooo much quieter, and cleaner, I've heard subtle nuances in music never before noticed. Like a veil was lifted from my system. This is the single most reveling tweak I've ever performed, even better than the green marker and the clock.
 
Ok, sorry. 

Honestly though,
The fan is quieter than the original by a noticeable margin.  With shipping it cost $20.10, including the sixty five cent discount code I found on Google.
>> HERE << is a link to the fan. Note, this is for the 10mm unit, they also have 20mm units. I almost bought the wrong one due to not paying attention. If your case fan is audible, you'd noticed a difference with a "hotrod" fan. I've bought fans from this company before and they've all been "ultra quiet" as advertised.

Bob

[satfrat]

Out of the 2 reviews Bob, 1 mentions a 3-4 month life span. They don't get any more quiet than when they stop running so good luck down the road. 
 
Cheers,
Robin

[Bob in St. Louis]

  I didn't see that.
Thanks for pissing on my Wheeties Robin. 

I still love ya though. I'm sure those that have had bad luck with these fans are carrying a truckload of negative karma. They simply lack the massive cool factor a "dude" such as myself has. I expect this fan to have a long and healthy life.

Bob 

[satfrat]

   You're welcome Bob.