@Kraken da Mabini, i'm often leary about gluing since my track record of glued things lasting is very not good. I mean, i guess there may not be anything to lose as long as i don't do any more damage but i really don't have high confidence - especially when there is pressure internal to the knob (some that keeps the knob in a position and the rollers that let it turn - i think).
@phxazcraig, no. I discovered the hairline crack between dives as I was articulating the knob and it turned too far - the mode position stopper didnt work. I'm guessing it came from being dropped on the table by the crew after the previous dive. Anyway, as I was playing with it trying to see what was wrong the plastic piece completely broke and a roller came out. As it is, the mode doesn't change as you turn the knob, so it is non-functional even if it wouldn't end up flooding or causing any other damage to the strobe. Prior to this, i've had zero problems with it.
@Tinman, understand and agree. But i wasn't so much looking for a quote, just a WAG. See above for my concern about gluing, but maybe it's worth a try? i guess? I'm not all that attached to the YS-01 but I was kind-of hoping I could keep the strobe for a second 'generation' and just replace my old camera/enclosure.
Thanks all for the responses.