Addressing "Frankenstein-ed" 5-Pin Dell Fans?

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root_user

root_user

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  • #1
    All-

    Is anyone aware of a way to regulate the speed of Dell's proprietary 5-pin fans when used in an aftermarket setting?

    I re-pinned two identical 120mm Foxconn fans (from a retired Precision T5500) to match the pinout of a standard four-pin Molex fan header - PWM, tach, 12V+, GND. However, when plugged into a more generalized board - (MSI Z390 A-Pro and MSI B550 "Gaming Plus" to be specific)... they both run at full speed with no change when attempting to alter such in BIOS. I have yet to try this with some near-identical models from Nidec, Delta, NMB and what not... but am guessing it is no different.

    Is there a proprietary microcontroller inside these fans that calls home to the OEM board to allow full functionality? Would be glad if anyone could assist in debunking these, they are nice fans.

    DELL 5 pin fan.png

    NN495__67061.1431621780.1280.1280.jpg
     
    R

    reckless_sniper

    Ars Tribunus Militum
    2,599
  • #5
    Either that or the fan is old enough that the "PWM" pin is actually a locked rotor alarm pin. But likely it's that the motherboard cant give enough power or uses different voltage(3.3 vs 5v)/frequency over the PWM pin so it gets screwy.

    IME. i had trouble with a (delta) blower reverting to 100% below a certain PWM threshold, and none of the PWM boosting techniques seemed to fix it.

    Also coming from someone with an MSI board recently, there's a setting in the bios' hardware monitoring page to change fans over from DC to PWM control for speed, that might also be screwing stuff up.
     
    steelghost

    steelghost

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  • #7
    "Yeah, but I have a perfectly good* fan right there!"


    reckless_sniper said:
    Also coming from someone with an MSI board recently, there's a setting in the bios' hardware monitoring page to change fans over from DC to PWM control for speed, that might also be screwing stuff up.
    Click to expand...
    If your board can force DC control, you might be able to just use that. It won't be as good as PWM control, but it might work Well EnoughTM

    *If Dell hadn't f***ed about with it
     
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