Laptop CPU fan Question

[Maplez]

I need a new cpu fan (PABD19735BM) for my old laptop and noticed something interesting. I found a CPU fan that was the exact same as the one for my laptop (casing and screw holes) but used a 4 pin connector instead of a 3 pin, could I buy the 4 pin fan, remove its blue wire, and use it in my laptop while keeping fan control?

With my old 3 pin fan when I accidentally cut the yellow wire the fan started to go to max speed then min speed repeatedly but from what I can tell online the yellow wire should only be a rpm sensor wire which means it shouldn't determine the speed the fan runs at.

 

Tbh I'm just curious if I could use the 4 pin fan, it's the same speed, voltage, current, housing and motor just with an extra blue wire and more fan blades

[RONOTHAN##]

15 minutes ago, Maplez said:

With my old 3 pin fan when I accidentally cut the yellow wire the fan started to go to max speed then min speed repeatedly but from what I can tell online the yellow wire should only be a rpm sensor wire which means it shouldn't determine the speed the fan runs at.

What likely happened there is the fan controller started acting up. It expected an RPM reading, and the fact it wasn't getting on threw it for a loop, causing it to do this. 

 

 

You probably can do this, though you would need to splice on a new connector (probably salvaged from the old fan) in order to get it to install correctly in your laptop. The 4th pin is just for PWM, and controlling PWM with just DC is very much doable. 

 

Just because of the need to splice on a new connector, I'd try to just find the 3 pin version so I wouldn't have to bother. If you can't find it or it's extremely expensive, sure give it a shot, but I'd have this be plan b rather than the primary solution. 

[Maplez]

9 hours ago, RONOTHAN## said:

You probably can do this, though you would need to splice on a new connector (probably salvaged from the old fan) in order to get it to install correctly in your laptop. The 4th pin is just for PWM, and controlling PWM with just DC is very much doable.

So I could just not use the fan's blue wire and keep fan speed control since the old fan didnt have one?

9 hours ago, RONOTHAN## said:

Just because of the need to splice on a new connector, I'd try to just find the 3 pin version so I wouldn't have to bother. If you can't find it or it's extremely expensive, sure give it a shot, but I'd have this be plan b rather than the primary solution. 

Both the proper 3 pin and 4 pin cost 50$, just the 4 pin spins slightly faster and has significantly more fan blades

[TPCEA]

49 minutes ago, Maplez said:

So I could just not use the fan's blue wire and keep fan speed control since the old fan didnt have one?

Both the proper 3 pin and 4 pin cost 50$, just the 4 pin spins slightly faster and has significantly more fan blades

As @RONOTHAN## explained, you can replace the plug and not use the 4th wire, whichever color that one is.  The 4th wire is for PWM control so, unless your laptop supports a 4-pin (PWM) fan, the best you can hope for is that there is space for that plug... otherwise you must mod the cable. 

 

If you have the skill & will to mod the 4, and you believe that the PWM is better then get that one. 

[RONOTHAN##]

1 hour ago, Maplez said:

So I could just not use the fan's blue wire and keep fan speed control since the old fan didnt have one?

10 hours ago, RONOTHAN## said:

Yeah, PWM control on a fan isn't necessary.

 

1 hour ago, Maplez said:

Both the proper 3 pin and 4 pin cost 50$, just the 4 pin spins slightly faster and has significantly more fan blades

I would still get the 3 pin. More blades doesn't mean more better all the time and the fact it spins slightly faster might still mess with your fan controller given the behavior it's had in the past. 

 

That said, $50 for a fan is rather insane. I'd spend a bit more time looking to see if you can find one a bit more reasonably priced ($10-30 would be where I'd expect).

[TPCEA]

1 hour ago, Maplez said:

So I could just not use the fan's blue wire and keep fan speed control since the old fan didnt have one?

Both the proper 3 pin and 4 pin cost 50$, just the 4 pin spins slightly faster and has significantly more fan blades

He made a good point about the price, but he always good points.  What country are you in?

[Maplez]

1 hour ago, RevGAM said:

He made a good point about the price, but he always good points.  What country are you in?

Canada, it's just the cheap 20$ fans are slower (3200rpm) and are missing half of ever other fan blade, this allows for the fan blades to warp. The 50$ ones are the proper fan that spins at 5000rpm and is not missing part of every other fan blade. Since I'm running an i7 4940mx that likes to pull 71 watts stock plus a 100 watt gtx 980m I'd like to use the 4 pin fan that has the same motor but more fan blades.

 

1 hour ago, RONOTHAN## said:

I would still get the 3 pin. More blades doesn't mean more better all the time and the fact it spins slightly faster might still mess with your fan controller given the behavior it's had in the past.

You think? The stock fan couldn't even keep the i7 4940mx cool while at max speed, it's why I'm even considering the one with more fan blades.

It would really have helped if msi put an air intake under the fan