we have up-graded our ARIA machine to an ARIA II a few month ago. Ever since then, the forward scattering is not always stable. It is either shifting slowly, or "popping" between 2 locations, that means cells laying in a nice fsc-a/ssc-a gate suddenly does not any longer. That happens even during the sortings. The drop picture does not change and looks nice. And most oddly none of the fluorescence markers/ channels is effected. Also the sort purity is fine. Just if my cells lay out side the gate, they won´t be sorted ; )
We had the BD technicians here a few times, they changed detectors for the FSC, but the issue remains and they seem not to have a clue...
Has anyone out there seen something alike and know how to solve the issue? That would be just so great.
Thank you in advance.