There is a 3mm or so thick cap on top of the big head that is used for focusing. If you are turning the big head that is incorrect first loosen the small cap on top a couple or three turns. Then hand tighten the big head down and leave it there. The focusing is done only with the cap on top.
regards
sbdwag
I can pinpoint focus my dilda easy, it took me a while to do it but now i can.If you can't focus it properly... try using a Magnifying Glass..
BTW... It is easier to focus the laser's beam to the smallest dot
if you use Laser Safety Goggles...
I assume you have a pair of Laser Safety Goggles for your 200mW
Laser...
Jerry