KB000183: What does Error "Quad DC Fault" During the MSD Ion Optics Test Indicate? - LC/MS ChemStation 

With the LC/MSD ChemStation rev. A.05.02/.04 software, the MSD Ion Optics Test in Diagnosis will often give a "Difficulty with ion optics electonics... Quad DC Fault" when it does the 'On Maximum (Neg.)' part of the test. This is a problem with the test, so don't troubleshoot an instrument problem because of this particular failure of the test. This fault in the Ion Optics test will be corrected in rev. A.06.01.