Here's my situation:

enter image description here

One of these:

enter image description here

I'm wondering if it's ok (safe, etc.) to solder the 2 black wires together, and the yellow + red together, and just use the 2 pin connector, eliminating the molex entirely?

Up until now, I plugged the 2 pin from the fan into the mobo header, and left the molex unplugged; that lit up the LED on the fan, but the fan didn't spin, so it looks like the pins are only used to light the fan, and the molex actually gives the fan it's power.

Just bought this expensive mobo, so don't want to take a chance of frying anything out w/out asking first, lol.

(before anyone asks, I know I could just buy another fan ... for 20 or 30 more bucks, but other than this situation the fan is good, 120mm cooler master fan).

Update: Here's a diagram from the mobo manual:

enter image description here

  • Try your idea without soldering and a small external power supply (usually 12 V or variable).
    – John
    Nov 19, 2021 at 22:38
  • @John I was also planning to try that as well, but was also wondering if it would have any negative effect on or from the mobo itself? Nov 19, 2021 at 22:42
  • You would need to look at the motherboard and determine the voltage and polarity of the socket. Fans usually do not draw much current. You can check the current draw in the temporary setup with a digital meter.
    – John
    Nov 19, 2021 at 22:43
  • 1
    I don't have the expertise to post an answer, but I would caution there is likely risk. The yellow wire is 12 volts, but I posit the red wire will only be 5 volts, and I would not be surprised if it is PWM modulated as well. If you wire the yellow wire to the red wire and power it off a 5 volt source the likely scenario is the fan will spin a lot slower. I imagine if its connected to a PWM line it will be even worse.
    – davidgo
    Nov 20, 2021 at 2:31


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