2 Replies Latest reply on Oct 18, 2017 9:10 AM by morlab

    7890B Signal Attenuation and Noise


      Anyone have experience with a 7890B causing abnormal signal attenuation and more signal noise than normal?


      The attenuation problem - the detector's AIB signal has a maximum signal of ~ 69,000 uV however the signal now tops out at ~30,000 uV in the ChemStation signal.


      As for the noise, it is 3x or more than the normal noise and occasionally gets worse, particularly when the signal tops out at 30,000 uV. The same GC has an FID and it is experiencing similar noise issues as the AIB signal.


      The problem has been isolated to the 7890B itself. The detector + AIB board was moved to a different GC (7890A) and all the signal problems went away. Also that 7890A's FID has been working properly as well.