The lab that I work at uses a Countess II FL cell counter and the machine typically works fairly well. Recently we have noticed that the lighting for the brightfield is uneven and causes cells to not be counted correctly. While searching for a fix we found the issue in the user guide; however, resetting the light cube tray and updating the system did not change the lighting. Any idea on a fix?

The image attached shows a band of uncounted cells due to the uneven lighting.