Did you inject a sample after the second autotune and have even worse sensitivity?
If the sample response is the same even with the bad second autotune then I would say look and see if you have any PFTBA left in the vial. I have had times I thought my instrument was dead only to find I had run out of PFTBA. If that is ok, then try another multiplier if you have one. I have had the K&M multipliers go out rather quickly sometimes, but not always.
The peaks are a little wide at 219, but with such low sensitivity I don't think that is pointing to problems with the side board, or quad drivers.
First thing I would do after checking the PFTBA volume would be to switch filaments and see if that has any effect. Could be as simple as a broken or sagging filament. Sometimes a broken filament will still arc and put out enough energy to let the tune run.
After that maybe clean the HED. That is the little metal button after the quads and before the multiplier. You can remove it by removing the two screws holding it in and sliding the wire out of the connector. Clean with isopropanol and a kemwipe, especially the metal part facing the quads/multiplier.
Also, is your vacuum down to at least 5*10^-5 torr?
Those are the easy things to do, after that you have to start thinking about electronics.
Side board electronics can make it do many strange things when they go out. It houses the quad drivers/mass filter electronics and the first part of the electron multiplier signal processing. Mass filter problems usually show up as drifting peak widths over time. You tune it then the next day your peak widths are far wider than normal, you adjust again and it repeats every day.
Main board electronics usually result in a dead instrument or errors like no emission current because it won't send power to the filaments.
If I can think of any more things to try I will post again. Let us know what happens if you check those first few things I listed above.
