2 Replies Latest reply on Dec 21, 2009 11:20 AM by mechbob

    DP35DP: Fan headers not working properly


      I've had this DP35DP for 1.5 years now as my primary workstation.  It has been rock solid.


      I have always had 1x 120mm intake and 1x 120mm exhaust fan attached to the 3-pin fan headers.  Of course, there's the CPU fan header.


      Everything has worked properly, and BIOS has always reported the proper fan speed (RPM).


      Recently though, the exhaust and intake fan headers started to report my fans running at about half of their rated speed (1000RPM).  They are actually running around 500-600RPM and I can notice the difference.  Case is definitely warmer, and just putting my hand across the fans, I can feel much less pressure.


      And yesterday, the exhaust fan header stopped reporting the fan speed altogether ( 0 RPM) - although the fan continued to run, albeit at a slower RPM


      Here's what I have done so far:


      1. Changed to latest BIOS, changed to last 3 BIOS versions.

      2. Changed every possible configuration in BIOS related to the fans (aggressive, high, auto detect, next boot, disable, etc) - you name it, I've tried it!

      3. Plugged  exhaust/intake fans on CPU fan header (they are reported on right RPM, and actually run at that rated speed, 1000RPM.)


      I haven't changed anything on the system except upgrading the videocard from a 9600Gt to a GTX 275.  Though, even after I upgraded to the GTX 275, the fans did work properly for a good many months.


      PSU (Corsair HX620) voltage is fine.   Everything well within range.  Nothing complicated with my hardware setup either.


      Again....this happened randomly.  NOT after installing or removing a component.


      What could be the cause of this and how can I resolve?  I'm not concerned about the RPM being monitored correctly per-se, I'm more concerned about that this erratic behavior by the fan headers will eventually lead to some sort of larger and imminent failure. (i.e. all fan headers stop functioning)


      Thanks for any help!