Yes, I know they're really cheap and I'd be better off buying another than trying to fix one, but this one's in nice condition apart from this issue and I'd like to learn another repair skill. This Trip 35 has a focusing problem whereby the front lens element (the one that ought to move in and out as you turn the focusing ring) seems to come unscrewed as you focus from far to near, so that it moves out when you focus in that direction but then stays still when you refocus back the way. You can manually screw it back in again, then the next focusing turn will work as before, and so on. It seems as if the front element and the focusing ring have come loose from each other, or out of alignment so they don't stay locked together. It was cheap enough that I'm happy to have a go at sorting this out. I see 3 tiny screws around the edge of the front lens element. What would happen if I undid those? Any advice or experience to share?