Are there electronic checks that can check to make sure a filament isn't failing because of an electronic issue?
We had a filament die, which isn't too surprising considering it was nearly ten years old (teaching institution, the instrument sees periodic use). We switched to the second filament and ordered new ones. But the second filament didn't last past the auto tune that I used to verify it was functioning. (Professor was unable to auto tune the next day.) I'm inclined to say that this filament failed due to age (again, it was almost ten years old), but I would feel better if there was a diagnostic test I could perform on the electronics before we fire up a new filament.