Odd fan behavior on (some) restarts

[t0ast]

System specs in sig and all fans in my case (except one 80mm panaflo, which is irrelevant in this situation) are powered through the motherboard.

 

EDIT: It should probably be noted that those two fans are in spots that allow the motherboard to control the speed

 

I've noticed after some restarts, two of my fans (HSF and one panaflo) don't start up with the rest of the system. Also, the temperatures all read -128C (in SpeedFan and BIOS) when this happens and the rest of the system boots into windows without a hitch. As soon as I see this and shut down the system, the two fans that weren't spinning turn on and remain on, despite everything else remaining powered off. When I try to turn on the system again, those two fans that were spinning while the system was off turn off and the rest of the system starts up again w/o problem.

 

The only way around this I've found was to just switch off the PS while the system is turned off (with the exception of those two fans). Starting up the system after that restores normality and it works until some restart down the road launches it into this wierd state again.

 

Any ideas as to what may be causing this or how I may fix it?

[mklint000]

Try not to power any of your fans through the motherboard. That should fix your fan problem and give your motherboard cleaner power. Although i'm not sure what would cause that in the first place.

[cpuz]

Try not to power any of your fans through the motherboard. That should fix your fan problem and give your motherboard cleaner power. Although i'm not sure what would cause that in the first place.

I agree, could be some bios setting for fan control that is causing that. I would not power the fans thru the mobo. Instead, use direct connections to the psu with a cable such as this

[Guest bobyjo]

mklint000 is correct, the power regulater in the motherboard is taxed enough with the components installed in your system.

 

If you add the fans to the task, you may be overloading that regulater.

This causes the mosfits to overheat, sometime a failure can happen.

 

Most everyone attaches thier case fans to the 12v leads that are from the powersupply.

This way they have nothing to do with the board.

 

These new boards are power starved in one respect to start with. If you add to that load, you could have poor performance, random rebooting, instability and the such.

 

If you need adapters to plug 3wire into a 4plug lead, they can be purchased from most any computer store to supply house.

[t0ast]

Alright, cool. Thanks guys. I'll have to give that a shot as soon as I find a local place that has those adapters in stock (CompUSA only had one in a cheapo NB HSF replacement kit)

 

One last thing, would it cause any unneccecary stress on the PS to chain 2 (maybe 3) of those off one line (assuming nothing else major is on it)?

[AndrewZorn]

i have the CPU fan and 1x120mm fan plugged into my board.

 

this is bad?

[Guest bobyjo]

Plug the 120mm fan into a powersupply lead.