My tune signal was low, and I just changed the Electron Multiplier Horn.
I checked in Agilent website and for MS 6120 should be part#
This looks identical from the old one, except for the color:
Once, installed, and got vacuum, I autotune. The signal boosted... maybe too much, since the autotune failed with this error message:
Did I get the wrong EM horn?
Is there any other way I can fix this?