Detector gain calibration?

[Wissenschaft]

I have a Thermo DSQ GC/MS that I am trying to tune and it keeps failing the detector gain calibration. What is this even for? And how can I make this pass? I put in a new PMT and it seemed to help he tune I did right after that, now 2 weeks later it is failing again. Website, book, explaination... anything, please help me understand!

[rumbakis1]

Detector gain calibration adjusts the voltage to the detector to reach a spacific gain. It can be unchecked in the Autotune menu. It is not necessary to be run as often. If it fails probably the ionisation is not good and intensity of ion 100 is low. Did you clean the source? Did you change the filament? Is the column installed correctly? Changing detector is last resort. I believe the DSQ uses electron multiplier not a photomultiplier, but may be there are some like that.