System Fans/Motherboard Been Searching For an Answer

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Aug 9, 2007
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18,510
Hello Everyone,


I have been having a problem with my motherboard reading my case fans' rpms (showing System fan speed at 0 rpms but displaying NB fan speed and CPU fan speed) as well as the case fans needing a push-start when I power up my PC. I have an MSI K8N Neo4 mobo with updated drivers. My case fans are stock coming with a thermaltake case. I have connected my case fans to the 3 prong headers to the mobo and I have also connected them to the power supply. I have many thermaltake 2 dollar fans that I have tried and either they don't run at all or they run slower than they should. I have returned the power supply and gotten a new one and same result (both were Antec 550W PSUs).

Help would be greatly appreciated considering I have been searching for an answer to this for two years now.


Thanks
 
You should connect the fan's power either to the motherboard or the molex.
I connect the power to the molex and the black single wire to the motherboard for monitoring. Some Bioses cannot detect fans moving slower than 1,500 rpm.
There may be a setting in your bios controlling the speed of the fan and at what temperature it kicks in.
 

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My fans are connected to the molex and I have also connected them to the SYSFAN headers on the mobo for BIOS reading. My fans may or may not be moving slower than 1,500 rpms, I'm not sure. I have not been able to control the fan speed in any programs or in my BIOS I guess because it's undetectable and I have no reason why.

I have a 550w PSU (Antec TruePower II) which has already been returned. So this is not the original and I'm still having the same issues. I have tried reconnecting the headers as well.
 

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ok, I just spun it with my finger as fast as I could and it read the fan speed at 689 rpms and then went back to 0. Now I know that it can read it, but I'm wondering why I can't make it go faster with these fan speed programs or at least make my fans go faster. They are connected to the PSU correctly and directly. Any ideas? My NB fan is running in the 6000s and my CPU fan is in that range as well.
 

Mondoman

Splendid
You shouldn't be connecting a single fan to *both* a molex power connector and a MB fan power header.
Also, some case fans draw too much current for the MB fan power header to supply -- they need to be connected to the molex.
 

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My case fans only have a molex power connector. The other is only a yellow wire which allows me to connect it to the SYSFAN1 header on the MB so I can take advantage of the MB sensors and fan controls. It doesn't have a GND or a +12V wire on the MB 3 head connectors. Only the sensor wire (yellow).
 

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any ideas? or has everyone just concluded it has to be the power supply? the voltages on all the components are fine...i have no idea what's going on.
 

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alright well since noone else has an answer to this, I guess it's the fan molexes. I tested the power from the PSU's pins to the MB and they are perfect but apparently the molexes are fucked for some reason. Never gettin Antec again.