please help with new build

  White_Elephant 18:45 05 Apr 2007

Attempting a newbuild but can't get power to the fan.
what happens is I connect the psu and press the power button on the case. The fan turns for a second then stops. I immediately disconnect the pwr each time so as not to fry the cpu and sometimes when i do this the fan suddenly starts up at full speed for a split second then stops as power is withdrawn.

Thing is, it cant be psu as i have tried 2 with same result. Getting really frustrated, any ideas?
Could mobo be buggered?

Intel e4300 with retail heatsink and fan
Gigabyte LGA 775 - 965p mobo
500w (20 + 4 pin psu)

  skidzy 18:51 05 Apr 2007

Sounds like a mobo fault,possibly the boards sensor kicking in and cutting off the power.

You are talking the PSU fan and not the heatsink ?

  White_Elephant 19:42 05 Apr 2007

sorry, i mean the cpu fan.

  skidzy 19:43 05 Apr 2007

The heatsink ?

If so,replace this first,cheap enough on Ebay or Pc world/Maplin etc...

  skidzy 19:44 05 Apr 2007

Just a quick thought,you did apply the thermal compound when fittin gthe cpu and heatsink...didnt you ?

  baldtaco 19:58 05 Apr 2007

Are you trying to run the fan from a motherboard header rather than a molex?

  White_Elephant 20:08 05 Apr 2007

answers: yes the heatsink fan is connected to the cpu_fan connector on the mobo.

Baldtaco: Im really not sure how to run the heatsink/cpu fan from a molex leading from the psu as they are not compatible - psu molexes are female same as the fan molex, you would surely need an adapter fitted with 4 pins like the mobo connector, that begs the question, why not just use the mobo pins?..

  laurie53 20:28 05 Apr 2007

I don't know much about this but I thought that with modern boards the fan only cuts in when required, not permanently?


  baldtaco 20:43 05 Apr 2007

White_Elephant, hola

It can put too much drain on the mobo. Without knowing exactly which fans you have I'm guessing, but I know some of my Deltas and two of my Thermaltake state very specifically that you will damage the mobo if you try to run them from a header.

  White_Elephant 20:48 05 Apr 2007

must say, i'm getting a bit confused now.
Laurie53 - surely the cpu fan runs constantly. Fan speed can vary according to load but you never run a pc without an active cpu fan.

Baldtaco, can you explain how to power the heatsink fan without attaching its molex to the mobo?

  White_Elephant 20:59 05 Apr 2007

not trying to spam but just to clarify as there seems to be confusion, my problem is:
cpu/heatsink fan turns briefly on power on then stops. Not sure why. Psu is fine, no physical obstructions to fan.

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