DIAGNOSIS
Check the imaging stream in GDA:
The imaging stream may look like either of these two options.
If the stream looks like above and the frame number is updating then the camera is on but there is no beam.
Open the shutter
Check the beam selector
If the frame number is not updating:
Check stream is on
This is the imaging stream receiving the imaging beam (above).
Check that the sample is in the FOV
Run through this checklist if you are unsure of what the issue is