Has anyone come across error 4, "Projector failure?"

I've taken up a project from a couple of years ago (started by someone else who has since left the company), using Cognex 3D-A5120 camera for robot pick-and-place application.The camera hasn't been used in over two years. Apparently it used to work fine back then, but is now displaying error 4, which corresponds to 'projector failure' in the manual.I'm perplexed because the device used to work fine, hasn't been used for a period of time and is now not working for some reason.Has anyone else has this problem before? Are there any solutions to this error, short of replacing the device?Many thanks