Solved! 3 pin CPU fan not working on 4 pin socket (LAPTOP)

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Jan 9, 2019
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Hey folks,

My laptops CPU fan died recently and I ordered new ones and replaced it. I had no idea what a 4 pin or a 3 pin was until today. I had no problem pluging the new 3 pin to 4 pin socket on motherboard but the fan is not spinning, no movement at all. Now before writing the specs I will tell you what Im already sure of :

The CPU and GPU fan socket for connector are working fine.
I had ordered 2 new fans (3 pin) and both are not working on this 4 pin socket.
The fans are also not working when plugged in GPU fans socket (which is also 4 pin).
I plugged both fans in these positions (l l l) l and. l (l l l). Not working.
The fans are not working on any fan speed level.
There are no other sockets in laptop for fans other than these two 4 pin sockets.
There are no options about the FANs in BIOS settings. (MSI fan speed can be observed and controlled by Dragon Center)
The new fans product code are PAAD06015SL N285. Old one was PAAD06015SL N402. They are both 0.55A 5VDC.
I have updated the BIOS.
I have updated the EC.
I have reseted fan settings.
I have updated MSI Dragon Center.
I cant find any option in BIOS or Dragon Center to run the fans on DC mode.

Laptop model is MSI GL72M 7RDX

From what I read on here and there a 3 pin fan should work fine with a 4 pin socket, just will spin at 100% speed at all times. Before assuming I was sent broken fans, can anyone tell me what could be the reason those new fans are not working?
 
Solution
This is not the same circumstance of connecting a 3-pin fan to a desktop motherboard's 4-pin fan header. Laptop fans do not follow the same standards. I recommend purchasing compatible fans (PAAD06015SL N402) for your laptop. I do have to warn you of the possibility that you may have damaged the fan or the fan header on the motherboard.

Links to compatible fans:

https://www.ebay.com/itm/New-MSI-CPU-Cooling-Fan-PAAD06015SL-N402-4-Pin-/263585887957
https://www.aliexpress.com/item/NEW-CPU-COOLING-FAN-AAVID-THERMALLOY-PAAD06015SL-0-55A-5VDC-N402-4PIN-E332100042MC200H37262066/32837717151.html

lolnole

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Oct 2, 2018
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This is not the same circumstance of connecting a 3-pin fan to a desktop motherboard's 4-pin fan header. Laptop fans do not follow the same standards. I recommend purchasing compatible fans (PAAD06015SL N402) for your laptop. I do have to warn you of the possibility that you may have damaged the fan or the fan header on the motherboard.

Links to compatible fans:

https://www.ebay.com/itm/New-MSI-CPU-Cooling-Fan-PAAD06015SL-N402-4-Pin-/263585887957
https://www.aliexpress.com/item/NEW-CPU-COOLING-FAN-AAVID-THERMALLOY-PAAD06015SL-0-55A-5VDC-N402-4PIN-E332100042MC200H37262066/32837717151.html
 
Solution
Jan 9, 2019
5
0
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Fan header is not damaged because I can control with my old fan (I know I wrote its dead but actually its still spinning). I dont understand why it doesnt work when both fan work on the same current and voltage. Is there any way at all to make this 3 pin work on the 4 pin header?
 

lolnole

Proper
Oct 2, 2018
45
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From the images, the fans have the following colored wires:

4-pin old fan: Red, Blue, Black, Yellow
3-pin new fan: Red, Black, Yellow

You are going to replace the new fan's 3-pin connector with the 4-pin connector from the old fan. The wiring to the connector will follow the same color scheme. Double check to make sure you do not reverse the wiring.

Old fan wiring == New fan wiring

Red == Red
Blue == No wire
Black == Black
Yellow == Yellow

If you did it correctly, you can clearly see from the wiring why connecting the three-pin directly to the logic board did not work.

I am assuming the blue wire is for the PWM signal. Because of the lack of a PWM connection, the fan will be running at a constant 100%. The negative effects of this is an increase in noise, power usage and dust.
 

lolnole

Proper
Oct 2, 2018
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I commend you for doing the rewiring. It looks correct. Unfortunately, it still doesn't work. I can think of two possibilities. The first possibility is the fan is faulty. The second possibility is the logic board shuts off the header when the PWM pin is not connected, which is a logical feature to prevent an uncontrollable fan.

I have exhausted my options with this fan. My only recommendation is to obtain a compatible 4-pin fan as I previously posted. I hope you are able to find a solution. If you are able to get this 3-pin fan to work, then I am more than interested in hearing how you did it.
 
Jan 9, 2019
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Thank you for your time and effort with helping, really appreciated. I'm thinking another option might be that I damaged one of the wires or the metal parts at the tip while rewiring (it's my first time doing it and I used a knife and tweezers). Since I have 2 of these fans I might try the other one. Maybe this one is faulty like you said.

If it doesn't work, I'm going to buy a 4 pin like you suggests. If it does I will repost on this topic and let you know.
 
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