Hello! I seem to be having a general background noise issue with my cypher AFM. I primarily do in liquid AC mode imaging of biological samples (virus capsids), and have noticed recently that the "noise" inherent in my initial amplitude seems to be increased. i.e. If i set my initial amplitude to a value of around 100 mV, previously I would see an error of approximately 95 - 110, whereas now it is more like 90-120 (all in-liquid). I moved to in air imaging and noticed that, again, I have increased noise in my initial amplitude compared to recent imaging sessions. Finally, I also observed that I seem to need a larger drive amplitude to get a reasonable tip oscillation amplitude, i.e. in the session I performed today a full volt of drive amplitude only elicited an oscillation amplitude of approximately 200 mV. Is it possible that the drive itself is going bad? could there be some other issue? At this point, the increased error is so bad that by the time I manage to land the tip on the surface it is too blunted to actually use (due to needing a much lower setpoint than usual to overcome the increased error in my initial amplitude), so any help and suggestions would be hugely appreciated. I have attempted to account for any vibrational noise, and outside of electromagnetic noise I believe any exterior noise sources have been accounted for. In imaging mode, if I manage to get a tip that is useable onto the surface, this noise in tip oscillation is manifesting itself as approximately 2 nm worth of background noise in my images, making them very difficult to do much of anything with.

Please let me know your thoughts or any additional information that you might need!

Thanks!