I have a 7890/5975C that has scans that come out like this. This started months ago. I have cleaned the source, inlet, replaced the copper tubing for my carrier gas and checked the manifold many times. My tune report looks normal aside from a bit of moisture. I haven't been able to find any leaks. Multiplier gain is low. Filaments are new. Ions also appear in the TIC as well. Where could this be coming from? I've capped the detector and it appears to go away. Could this be an issue with the electron multiplier? Am I missing something? This is a relatively new instrument to me.