A few years ago, I bought a couple of lasers from "Sci-Fi Lasers." I know that a whole bunch of problems occurred with that "company" but I had little issue with the chap in question. However, I need to repair the SF501B 445nm that I have. The lens has stopped focussing and basically, the unit works but is useless. What can I do to get this fixed? Can I buy a replacement lens for the thing? I'd like to use it again but I admit that I have a handful of thumbs when it comes to fixing stuff. Any advice would be great... Thank you in advance!