Seems a little less-likely to be the problem, given(?)
as well that you have fairly consistent (is deterministic overstating it?) behaviour.
Yeah. We've gotten to the point now where enough layered problems have been cleared
away that the remaining behavior is quite deterministic.
If you wanted to test it by experiment, without having
to remove the installed Rs, you could test-clip another R in parallel with the 38.4K,
probably something around 200K, to shorten the 555 period.
Yes; and I think a quick solder tack for that would even be easier to manage than clips in
there. Will give that a go this weekend.
cheers,
--FritzM.