CPU fan spinning at full speed

[Ika]

I recently received a Big Typhoon heatsink with a Silverstone FM121 fan attached (the 110cfm 120mm white fan). The fan came with a fan controller, so I thought that was nice. I was pretty sure I didn't want the fan running at full speed all the time. I installed the BT and the fan, and it ran fine; the fan controller did its job quite well. The fan had a single yellow wire connected to the 3-pin connector on my motherboard (CPU_FAN) and was powered through a "Fan Only" molex modular cable from my Corsair 520HX.

However, I turned my computer on today to find that the CPU fan was spinning at full speed, regardless of what I tried. Dialing down the fan controller does nothing, unplugging the 3-pin connection from the motherboard does nothing (except make the mobo complain that there wasn't a CPU fan installed), and BIOS settings don't do anything either. What's going on?

 

[Noubourne]

If your mobo has some automatic fan controller options, it might not like that you've added another controller (I know my P35 board thinks there is a problem b/c I have a Zalman controller in between it and my fan).

Try removing the extra controller and letting the mobo do it, or turn off all controller options in the BIOS maybe?

 

[Zepper]

Most mobos can't handle 110CFM fans - max the current is too high for a mobo fan header. Draw a wiring diagram showing how you have the fan hooked to power.

.bh.

 

[Ika]

As requested, a pic of my fan wiring.

However, something should be reiterated - the fan was working fine the past few days (fan control worked great). I don't really know if I changed anything (and if I did, I won't know what it was). I guess I'll just mess around with my fan control options and hope something works.

 

[Zepper]

I get an error "unauthorized referrer" when I try to access your pic.

.bh.

 

[Ika]

Originally posted by: Zepper
I get an error "unauthorized referrer" when I try to access your pic.

.bh.

it's bbzzdd. try typing it in manually if it still doesnt work.

 

[BonzaiDuck]

Originally posted by: Zepper
Most mobos can't handle 110CFM fans - max the current is too high for a mobo fan header. Draw a wiring diagram showing how you have the fan hooked to power.

.bh.

I think this is an overly cautious conclusion, and depends on the motherboard. On the ASUS Canterwood and Springdale boards [478-pin generation], the User Guide was fairly clear in stating that the total limitation for all fan headers applied whether only one or two fans drew the maximum current, or all fan-headers were used. On my old P4P800-SE, I've been running a 12V 0.80A fan off the CPU_FAN header for almost three years, and controlling it with SpeedFan. I've never had a problem with it, and if I want, (or when I come up from a cold boot), it will run the Delta tri-blade at its full-out top-end of 3,700 rpm. Never had a problem controlling that fan for any range of speeds.

I think it would be explicit in the mobo user-guide or spec updates to the board. But I discussed the matter with a physicist and a retired network-tech -- both suggesting that the cumulative amperage limit would apply to even a a single plug, given the way those circuits would be designed.

The boards I've used over the last few years typically have a cumulative 2-amp limit.

 

[Zepper]

Well, I still can't access your pic. I post my pix on photobucket.com and have no such problem with viewing. Anyway, perhaps somehow your speed sensor lead isn't making good contact or stopped working.

.bh.

 

[Ika]

Interesting. Try this link.

 

[Ika]

Bah. At this point, nothing's been able to fix my FM121. I think somehow the controller or the fan itself fried something to do with voltage regulation... what a bother. I took it out of the case and replaced it with an Antec TriCool that I had (blue LED, to match my color scheme ). I would really love to take a look inside the silverstone to see what makes it tick... any way to get to the circuit board without ripping up plastic? I can see the soldered connections to the wires that go to the fan controller, but I don't *see* anything loose or disconnected... maybe I'll poke around with a DMM.