Weird intermittent POST error on A8N-SLI

[Mudbone]

I just finished building my new rig. A8N-SLI with a 3500+ and stock HSF. I went through the case one last time, hooked up an internal card reader and the front ports to the mobo, then moved the case from my work table into my office. Now I am getting a strange intermittent error on power up. It beeps several times and then gives the message, "Warning: Your Computer CPU Fan Fail." and "press F1 to continue, del to enter setup." The deal is there is nothing visually wrong. I shat the first time it happened and pulled the side off the case. The CPU fan and the chip fan are spinning normally. I checked the connections to the mobo. They appear fine. The fans start spinning immediately I did ten power ups this morning and it happened 3 times, all in the first five attempts. After that it didn't occur anymore. There was no visual difference in when or how the fans started up when it gave the error and when it didn't. It always happens on the first power up if it hasn't been turned on in awhile IE, overnight.

Any ideas?

 

[imported_2x]

This is common to this board. Others have had this message. I get it about once every 25 boot-ups. Probably will be solved with a bios fix in the future.

 

[GuitarDaddy]

What CPU cooler are you using? Its most likely that your fan speed is to slow for the mobo to detect, I've read several posts with this problem. I know the panaflow fans have been reported to have this problem.

You can stop the boot up error message in bios under boot options, change to "stop on no errors", people with water cooling (no fan), and people who have fan reporting problems have been using this option to bypass the boot messages

 

[Mudbone]

That's interesting. GD I am using the stock heatsink and fan unit that came with the retail CPU. The case fans are what ever Lian-LI is using. I was going to upgrade when I got around to OCing. I flashed to BIOS 1004 and got a new version of the same message. The interesting thing is that the fan speeds in BIOS are way above the min RPMs selected.
IE the CPU fan speed warning is set to 1200 RPM and the actual speed is 3400 RPM.

UPDATE I just caught it doing it. I booted, went into BIOS and went directly to the Hardware Monitor screen. The CPU fan is spinning normally, (I've still got the side of the case off), but the RPM reading is 0. Then a few seconds later the reading spins up. Now it is reading 1500 not 3400. Hmmmmm. I think I am just going to disable the fan warnings.

 

[LTC8K6]

Then if the fan really does fail you'll get no warning. Not a good trade off, imo.

It's probably a timing issue of when the fan spins up versus when the BIOS checks it.

 

[MeatHead88]

This only started happening to me after I enabled QFan in the bios. Disable QFAN or reduce the minimum RPM the MBoard looks 4.