To undo the crimp on the ArcAAA, I:
- lay the head on it's side, at a 60º angle from a flat surface
- with the fine screwdriver in my Leatherman Micra I push the crimp up
- I go around the head, lifting the crimp slowly
and only half way up
- I then place the head upright and continue to raise the crimp some more
- I go around a couple of times, each round raising the crimp some more until it's completely vertical
- to make the pill extraction easier, I actually push the crimp outward by inserting the tip of the screwdriver between the crimp and the board and carefully pushing outwards - easy does it, push too much and you'll break the crimp :green:
When I reassemble the head, I just push back the crimp by rolling the packed head hard against a piece of flat metal. In only one light the user had ground problems later on. To fix that, you'll need to hammer the crimp using a large flat-head screwdriver (that's what the flat notches on trivergata's pic are from). You can also hammer around the crimp a little, but the screwdriver should do it.
Something else I've observed is that the crimp in some heads seems to be tougher than others. Most of the times I've undone the crimp cleanly by following the steps I described above, but a few of them...
I now re-pot the head with RTV, as I lost one head to epoxy contraction (shearing off some component is my guess - it was working fine before potting). If you're replacing the LED, it's also a good idea to test the fit of the new LED through the hole. Some LED's are a tad too big and then don't allow the board to make proper contact with GND (the LED get's stuck half-way past the hole and the pill doesn't slide in all the way like it's supposed to).
More on replacing the LED in an ArcAAA (and opening the head, etc.). Actually, it's a scary mod to do. If something goes wrong (and a lot of things can) you'll have a dead ArcAAA in your hands.
Proceed with caution. If you love your ArcAAA too much, don't mod it.