[SOLVED] Removing a case fan connected to the PSU

Jul 7, 2019
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Hi, I need to replace a dying case fan that was connected to the PSU cables by a technician a few years ago. The fan has a 3-pin molex connector that has had its cables attached to the PSU's molex 4 pin connector somehow. I'm really new to PC building, so I don't know what to do to remove the fan, because I don't know how they managed to connect it like this. I will post a few pictures. Appreciate any help.

1kiBzPC.jpg

gRZUyUP.jpg
 
Solution
Excellent info above. Further note. The old fan came with TWO connectors on the end of its leads for flexibility, but you must use only ONE of them. The way it was done gives that fan a constant 12 VDC power supply directly from the PSU to run full speed all the time. The alternative is NOT to use that particular connector. You can plug the smaller 3-pin female connector into a mobo fan header IF you have one available and of the right type, and then it gets power AND automatic speed control from that header. But the "trick" is that the header must be of the 3-pin type, OR if of the 4-pin type you must be able to configure it (in BIOS Setup) to use the older Voltage Control Mode (and not the newer PWM Mode). A 3-pin fan like that can...

Aeacus

Titan
Ambassador
See those two round bits (with grooves in them) on both sides of the molex connector? Press on them at the same time (e.g clamp them) to loosen the molex connector a bit. Once it's loose a bit, wiggle the connection point until you can separate them.

I can also post some pics if needed.
 
Jul 7, 2019
3
0
10
See those two round bits (with grooves in them) on both sides of the molex connector? Press on them at the same time (e.g clamp them) to loosen the molex connector a bit. Once it's loose a bit, wiggle the connection point until you can separate them.

I can also post some pics if needed.
Thanks a lot for replying! Could you post the pictures? I've tried clamping the connector and wiggling the cables but I'm not sure I'm doing it the right way.
 

Aeacus

Titan
Ambassador
Here's the image and steps as well:
  1. Top left - 2x molex connectors connected (black PSU side, white fan side).
  2. Top middle - Grab the connector as seen.
  3. Top right - Clamp down on connector as seen to loosen it.
  4. Bottom left - With it, connector is more loose (compare it to pic 1).
  5. Bottom middle - Now just wiggle it a bit to loose it even more. Grab the connector (plastic part), not the wire.
  6. Bottom right - End result: molex connector separated.
ZefdgN0.jpg
 
Jul 7, 2019
3
0
10
Here's the image and steps as well:
  1. Top left - 2x molex connectors connected (black PSU side, white fan side).
  2. Top middle - Grab the connector as seen.
  3. Top right - Clamp down on connector as seen to loosen it.
  4. Bottom left - With it, connector is more loose (compare it to pic 1).
  5. Bottom middle - Now just wiggle it a bit to loose it even more. Grab the connector (plastic part), not the wire.
  6. Bottom right - End result: molex connector separated.
ZefdgN0.jpg
Thanks a lot, that worked!
 

Paperdoc

Polypheme
Ambassador
Excellent info above. Further note. The old fan came with TWO connectors on the end of its leads for flexibility, but you must use only ONE of them. The way it was done gives that fan a constant 12 VDC power supply directly from the PSU to run full speed all the time. The alternative is NOT to use that particular connector. You can plug the smaller 3-pin female connector into a mobo fan header IF you have one available and of the right type, and then it gets power AND automatic speed control from that header. But the "trick" is that the header must be of the 3-pin type, OR if of the 4-pin type you must be able to configure it (in BIOS Setup) to use the older Voltage Control Mode (and not the newer PWM Mode). A 3-pin fan like that can only run full speed if it is used on a mobo header using the new PWM Mode, and that is exactly the same as doing it as the old one is now - direct to the PSU.

Since you are buying a new fan, depending on what mobo you have and what headers it has for your use, you may need to stick with the 3-pin fan type, or you may want to switch to a 4-pin PWM type of fan. If you stick with 3-pin and plan to connect it again to that Molex power from the PSU, you do not need the extra smaller fan connector on the wires of the new fan.
 
Solution