HED Fault

I had the same problem last week, after cleaning the source I had a HED Fault. I also saw a high baseline while tuning. According to Agilent probably a speck of dust some where on or near the HED or electron multiplier. Agilent has a PDF explaining how to clean those. After cleaning the HED and electron multiplier no more HED fault.

I had the same problem last week, after cleaning the source I had a HED Fault. I also saw a high baseline while tuning. According to Agilent probably a speck of dust some where on or near the HED or electron multiplier. Agilent has a PDF explaining how to clean those. After cleaning the HED and electron multiplier no more HED fault.

(+) Cleaning HED Detector Assemblies 5975-5977.pdf - Files - GC/MS - Agilent Community

I have already cleaned detector and EM. But still no change. 

There could be issues with either control signals to the HED power supply or the power supplied to the HED power supply.  These electronic issues are down in the depths of the instrument and should be handled by a trained service engineer. Please contact your local country's Agilent service.