Chromatography Forum

So we have a 20-year old 5975. About 15 years ago, I seem to recall a similar issue where the filament wasn't quite getting enough power and it was due to maybe a component failing on the board powering the filaments and it was ultimately bypassed by putting a dummy (CI) filament in the second position; the filament in the first position could then get enough power to turn on normally and it has worked perfectly fine ever since then.

Yesterday, no more signal and sure enough the filament is not lighting up; it's possible the sensitivity decreased prior to this as well. Well technically no signal, see below (no baseline but some random peaks in blank runs with low abundance, not always the same times or associated 'masses');



There is no error message in the software, and nothing shows up on the MS itself either. The EM horn is relatively new (maybe 1235 V now), the filament was switched out only a couple of months ago, turbo pump reports 100% in both software and on the MS, and the vacuum is in the 10^-5 range. Tried loading a different tune file, hard rebooting, as well as manual tune/profile scan (calibration valve opens as per click but no apparent signal);



I'm about to vent to try to perform more troubleshooting but anyone has an idea of what I should be looking for? Wondering if it could be related to the initial issue on the board from all those years ago or if perhaps it could be something else - it's odd that no error is being reported although I can't recall if this was the case back then either.

Also wondering if there are other tests I should perform first before venting it that could help in diagnosing the issue since I prefer to limit the number of power cycles of the MS given its age.


Thanks!

I would recommend swapping out the filaments for another pair. Our lab has had problems with faulty filaments in the past, in fact just recently we had this happen on a 5975. Swapping out the seemingly perfect looking filaments with another pair did the trick.