The mcpcb is not fixed in place, there are no anti rotation screws.
Head is fine to unscrew.
The tail cap should not be unscrewed.
Change the battery by unscrewing the head.
BTW, the optics and mcpcb are only effected if you try to unscrew the bezel on the head, which is not recommended. This is seperate from the head itself. You might be confusing these two things.
A mountain is being made of a molehill by some concerning the FW3A.
It is the same as any other light:
This is just all normal stuff that applies to ANY light, nothing more.
I sent Neal an email yesterday but havenāt received a response yet. Iāll make sure to request for replacement/return when he does reply, now that Iāve found the problem. This is the first time Iāve taken apart the head like that. It must have arrived like that, since it was never operational.
If you guys need better photos or the original, unedited photos for reference in this thread, I can go ahead and post/send them to you guys!
Alas, those used to be a feature, which some of yāall are too young to recollect.
EDIT: djozz described one here, around the time the assemblers forgot what the holes were for; they started showing up misplaced and eventually not even threaded, then quit appearing at all.
Circuit boards used to come with notches, the screwheads appeared in the notches, and the board wouldnāt turn.
Saved a nickel apiece by eliminating that step of the construction, perhaps trusting the thermal goop to be glue.
Ah, I know Iām a fossil remembering back when they used to build these things by hand.
This is sarcasm, in case anyone thought he was serious. :partying_face:
Waitā¦ by ābezelā I understand this to be the front most piece on the light. You need to remove that to get access to the optic. So why would it be not recommended? Iāve removed it about a dozen times thus far to experiment with different optics. No problems. I do not get any MCPCB rotation going on.
> anti-rotation screws
as described by djozz here: My impression of the Sofirn SC31, almost right - #4 by djozz
This front bezel gets a lot of folks in trouble. It depends on the light, though so some companies just glue it shut. Some lights have optics that sit on top of the mcpcb and if the optics get twisted you can dedome all your leds.
In the case of the FW3A, removing the bezel can twist the wires off the mcpcb. I didnāt know this was a possibility until just now. So we should all use caution when loosening and tightening the bezel and itās probably a good idea to apply some downward pressure on the lens to keep it from rotating.
Itās like TK says, the more you take a light apart and put it back together the greater the chance youāll break it. 
Ah, just noticed Berkleyā¦ā¦ā¦ā¦ spent a few months there in ā¦ā¦ probably ā68. āSpare changingā on Telegraph Ave and sleeping in Peoples Park in a ā59 Pontiac someone gave me in Huntington Beach. Those were the days
Berkeley was interesting back then. I still remember going to classes with all the National Guard and police walking around. And being teargassed wasā¦ā¦.interesting; especially when they used a jeep spraying teargas out of it and being stuck in traffic.
I guess āinterestingā is one word for thatā¦ā¦ āsucksā seems more appropiate to me however. 
Very true. Back then it was awful and really was a terrible experience. But now it doesnāt seem like it was all that bad since one tend to forget how bad things were long ago.
I wonāt even go to how āinterestingā it was getting shot by rubber bullets or how fast one can run when being chased by people with big clubs who had legal authority to use them :weary:
Ouchā¦. ārubber bullets & big clubsā could get āinterestingā real fast!! 
That really would āsuckā.
I guess looking backā¦. time does put a different perspective on things.
I figured that since the front bezel FW3A is attached using external screw threads on the body, unscrewing the bezel wonāt affect anything internally. The counter-clockwise rotation to remove it might cause the front glass to rotate for a small amount, but the optic definitely doesnāt move. I pop it out, then put a replacement optic into the 3 peg holes, lay over the glass, then screw down the bezel. Nothing internally rotates. But I hear you, that it may not be true for every assembly.
I will follow your advice, though. The next time I do it, Iāll take a toothpick to the MCPCB and check to see if itās well anchored in place or loose. I definitely donāt want to end up torquing the wires and cause them to detach!
Heyā¦ if you have not had any problems your obviously doing it right. I wouldnāt change anything. (And I did not suggest a ātoothpickā for anything eitherā¦ )
All I am saying is just because you have not experienced a problem does not mean someone else will not experience it.
I have found that a little bit of pressure on the glass lens with my thumb when removing or tightening the bezel on lights where the MCPCB can rotate is enough to prevent a problem. (after the first time I ripped the wires loose on one)
/\ ā¦ā¦
I have double check to make sure iām not in muggle mode.
Iām unable to go into Group 2 now.
When i perform click, click, hold ā¦ā¦it just respond by one dim flash/flicker and goes off.
Iām able to go into Group 2 the first time when i received this light and i was playing with all the Group 2 mode (candle, bike flasher, party strobe, tactical strobe, lightning storm). The last Group 2 mode i used was lightning storm.