I am using Agilent 6470A mass. Yesterday, I tried to check-tune it failed, and I have done auto-tune the results were okay. Again, I have tried check-tune today it failed and I checked with autotune. The error message popped up that autotune did not finish successfully. The process was stopped in calibrant and cell gas turned ON. can you please explain what I have to do? If possible please send me the tutorial for autotune and manual tune.