Aging detector limits

Is your multiplier at 3000? What is your system?

The EM volts is at 2000 on the last tune. This is a GC 7890B MS 5977B with a HES source. The acquisition system is MassHunter. 

When you run autotune MassHunter creates a gain curve for use with the gain factor setting.  When Gain Factor is selected in the method's MS Settings, the system will adjust the EM voltage based on the gain factor you enter and the gain curve created with the tune file.  The warning message indicates that you can't use a gain factor higher than 4.6 because that would require the EM voltage to be greater than 3000.

If the EM mode in MS Settings is Absolute or Relative, this wouldn't affect you.  Even if that's the case, it would be good to order an EM and replace it the next time the MSD is down for maintenance.

There's an older Agilent technical note about gain factor: www.agilent.com/.../5989-7654EN.pdf

thank you, this is very helpful