Help with Fan replacement

Discussion in 'General Electronics Chat' started by ebigs, Feb 7, 2010.

  1. ebigs

    Thread Starter New Member

    Feb 7, 2010
    4
    0
    Hello all,

    Wondering if some of you electronic guru's can help me out...

    Situation: I have a Cisco 3725 router that has 2 really really really loud fans. They're like 40+ db. I want to change these out to lower noise level fans (11db). This router sits on my desk in an air conditioned office, not in an equipment rack, so I don't need fans that are spinning 3000+, being so loud.

    The original fans are:
    NMB, 80x80x15, model: 3106KL-04W-B59. as far as I can tell these are the specs: 12V, 0.24A, 2.76W.

    I purchased these new fans:
    Silenx, 80x80x15, model: ixp-52-11. specs: 12V, 0.04A, 0.48W.

    In the past I've changed fans out in other router and switches where the Amps and Watts were different, but the Volts (12V) were the same and everything worked. With the above noted fans, they don't power on? Is there some type of regulator or circuit board kit I can purchase or make to get the new fans running in my router?

    Thanks in advance,
    Ebigs
     
  2. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    With the new fans, it should work considering they use less current than the old ones..... Are the pinouts on the fans the same (i.e. color coding on wires is the same for both fans?).....
     
  3. ebigs

    Thread Starter New Member

    Feb 7, 2010
    4
    0
    That's what I thought too. I think the new fan should work with lower amps? The new fan has 3 wires that are all the same color (Silver) and are about half as thick too. Do you think I can rearange the wires and just to a trial and error test without damaging the fan?

    The original fan has black, red, and white wires.

    Thanks,
    Ebig
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    From the looks of the packaging for the new fan, that it comes with a wired adapter with 2 wires on it.... do you have that adapter? That adapter is for powering the fan directly from 12 volts.... see which pins they line up with on the motherboard and see if the old fans red and black wire match up with that. The Red wire on the old fan is the +12, the black is ground and the white is for the speed control feedback.....
     
  5. ebigs

    Thread Starter New Member

    Feb 7, 2010
    4
    0
    Thanks BMorse! I'll take a look and post back in about 1 hour.

    Ebigs
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    On the origenal fan the red and black are the power connections.
    The white is a sense wire, the signal on that wire changes state when the RPM's drop below a certain level.
    This is to garantee a specified airflow.

    Greetings,
    Bertus
     
  7. ebigs

    Thread Starter New Member

    Feb 7, 2010
    4
    0
    A Big Thank You! All fixed and working good!

    Ok, here's what I did:

    The original fan has wire colors: White, Black, Red. In the order I'm looking at the connector.

    I plugged the 2 wire adapter on to the new fan, and then plugged this into my PC. This PC power adapter is the kind that you would use to power a CD/DVD, the bigger 4 wire type. Those colors are: Yellow, Black, Black, Red. With the two wires plugged into this one, they correspond to: Yellow, Black. Which in turn correspond with the Black, Red on the original, but in reverse order.

    So all I did was change the two wires that corresponded to the Black, Red wires, and it works fine. The white on (controller wire) was already in the correct spot.

    Many Thanks, Both BMorse and Bertus, you guys were a really big help!

    Ebigs.
     
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