HED Fault

Hello i asked earlier about HED Fault i encounterd

The Autotune gives error 

Filament turns off 

I check for air leak ... the door closes tightly immediately when the vaccum pump turns on 

Hi Vac is  N/C

And this is the error

  • Hi  @, there are the possible causes:

     1)make sure the solvent delay is long enough 

    2)  Vacuum is not good enough like the vacuum manifold pressure is too high

    3) HED high voltage lead is shorted to ground. please check  the HED high voltage lead. Make sure it is connected and not shorted to a grounded surface.

    4) the detector  is  contaminated, Cleaning the HED - 5973A/N (agilent.com)

    5) MSD electronics, it could be a problem with hed, hed power suplly or main board

    I appreciate your feedback,


  • Does your MS have a turbomolecular or diffusion high vacuum pump?   Does your system have a high vacuum gauge?

    How long has the system been pumping down before trying to tune?  It needs to pump at least an hour or more for good vacuum.

    Verify that there is PFTBA in the vial and that the nut holding the vial and O ring is tight.  If that O ring leaks a big burst of air flows in and the system will shut down like this.

    Try an STUNE, a standard spectrum autotune. That is a fast way to make sure it's not a bad tune file.

    It has nothing to do with solvent delay. It has nothing to do with a contaminated detector as it does not even turn on. If you did not remove it, the HED high voltage lead should not be disconnected. 

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