Strange fan issue

[Spork829]

My mobo has three chassis fan headers. Only number 1 is 4 pin PWM, the other two are only 3 pin. I've noticed that though the other two work fine, when I use a 3 pin non-pwm fan on that chassis fan 1 4-pin header, I have zero control over the fan whatsoever. It runs at full speed. No matter what I tell it to do in the BIOS, any fan I plug into that port just runs at 100%. Do I just have a busted header or what?

[Electronics Wizardy]

Nope, thats how pwm fan headers. The + pin is always 12v and the pwm, unlike the other ones where you control the + pin with pvm or a voltage controller.

[Spork829]

1 minute ago, Electronics Wizardy said:

Nope, thats how pwm fan headers. The + pin is always 12v and the pwm, unlike the other ones where you control the + pin with pvm or a voltage controller.

Oh I see, so you just can't do the basic voltage control through a PWM header at all. Huh okay time to order a splitter. Thank you  

[LogicalDrm]

15 hours ago, Electronics Wizardy said:

Nope, thats how pwm fan headers. The + pin is always 12v and the pwm, unlike the other ones where you control the + pin with pvm or a voltage controller.

 

That isn't really true with all mobos. Sadly it seems to be with OPs.  The pin layout is same for both header types, with exception that 4pin has 4th pin for PWM signal. With the three others being PWR, GND and RPM.

 

15 hours ago, Spork829 said:

Oh I see, so you just can't do the basic voltage control through a PWM header at all. Huh okay time to order a splitter. Thank you  

 

From what I can gather, Asrock has only one setting for CPU header and thats optimized for PWM. It might be a bug (you can try updating BIOS or using Windows software instead).

[Spork829]

6 hours ago, LoGiCalDrm said:

 

That isn't really true with all mobos. Sadly it seems to be with OPs.  The pin layout is same for both header types, with exception that 4pin has 4th pin for PWM signal. With the three others being PWR, GND and RPM.

 

 

From what I can gather, Asrock has only one setting for CPU header and thats optimized for PWM. It might be a bug (you can try updating BIOS or using Windows software instead).

This isn't even the CPU fan header, I'm talking about the chassis fan 1 header which is a 4 pin on my board. And I've already tried updating the BIOS, though I suppose it could still be a bug.

[LogicalDrm]

1 minute ago, Spork829 said:

This isn't even the CPU fan header, I'm talking about the chassis fan 1 header which is a 4 pin on my board. And I've already tried updating the BIOS, though I suppose it could still be a bug.

So profiles work with 3pin headers but not when you connect 3pin to only 4pin? That is weird. Only thing I can think is that header isn't connected to control chip.

[Spork829]

2 minutes ago, LoGiCalDrm said:

So profiles work with 3pin headers but not when you connect 3pin to only 4pin? That is weird. Only thing I can think is that header isn't connected to control chip.

Yep that's exactly the case. Perhaps I'll try out my CPU fan which is a 4 pin on that header and see if that allows me to control it then.