CPU fan error with 120mm NEXUS - help?

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CPU fan error with 120mm NEXUS - help?

Post by antonm » Wed May 10, 2006 5:51 am

I've got a new ASUS mobo with a 120mm NEXUS connected to the CPU 3pin fan header. The mobo reports a CPU fan error on BIOS POST with the NEXUS but not with the stock AMD HS fan. Both fans actually spin normally and speed varies with load etc., NO difference in functionality. Why the error with the NEXUS. The mobo instalation instructions mention: "If and AMD stock HS/fan is not used, an appropriate 3rd party HS with a thermally controlled fan MUST be used". What's a thermally controlled fan? Is the Nexus thermally controlled? Is this why I get the error?


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Post by qviri » Wed May 10, 2006 5:59 am

Without knowing the motherboard model, all I can do is guess that since the Nexus is spinning slower than the stock fan, the motherboard panics since it thinks the CPU will be undercooled.

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Post by shadestalker » Wed May 10, 2006 6:02 am

My guess would be that the Nexus spins slowly enough that the motherboard is alarming on a low or no RPM reading from it. Some headers don't register very low RPM.

The A8N SLI Premium has a BIOS menu option to turn off the CPU fan check. I don't know if this is common among other Asus boards.

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Post by cmthomson » Wed May 10, 2006 6:46 am

The fan error thresholds in the BIOS of my ASUS P5LD2 are very high, and couldn't be lowered enough to not give fan errors with Nexus fans. I had to set them to ignore.

Same deal with SpeedFan.

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Post by Felger Carbon » Wed May 10, 2006 9:10 am

My Asus K8S-MX mobos have a fixed 1800RPM CPU fan speed threshold that cannot be changed, only set to ignore. The RPM is then reported as zero, which causes SpeedFan to provide erroneous readings on thermal diodes, including the one in the SiS chipset and the one on the CPU die.

I wasted a day chasing an overheating CPU that wasn't overheating at all; I had turned off the CPU fan sensor and got hit with the SpeedFan bug. :(

I now accept the "hit F1, ESC" as part of the bootup sequence. :oops:

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Post by JimX » Wed May 10, 2006 2:21 pm

Felger Carbon wrote: I now accept the "hit F1, ESC" as part of the bootup sequence. :oops:
Same here...

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Post by Bluefront » Wed May 10, 2006 3:28 pm

My Asus board does the same thing with a Yate Loon at anything below 1000rpm. I switched to a Globe fan and the board reads the rpm down to 700 rpms, and starts without hitting F1.

I am tricking the board now by attaching a quiet 60mm fan to the CPU header.....it runs about 1200rpms at 5V. The board starts ok with this setup.

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Post by antonm » Thu May 11, 2006 9:40 am

Darnit all, I will have to set it to IGNORE rpm once the system is worked in and stable, because I find it too anoying. The board is an ASUS A8V with a X2 3800+ with one nexus as a case fan.

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