early legacy chuff switch question.

Chuff switches can just randomly fail. Where the chuff switch lives in relation to the smoke unit is one factor that can kill a switch in short order. Smoke fluid can turn to varnish, and render a chuff switch useless. However, in your case, I’d take a closer look at the IR parts again, beings you’ve just done some sensor work. Chuff can drop out intermediately if the sensors lose sight of one another,…….a tell-tale of such a condition is if the chuff sounds operate as advertised on straight track, but gets interrupted on curves. Also, grades can play a role in IR sensor alignment. ……I’d take a harder look at the IR sensors on that particular case if I were in your shoes…..

Pat

thanks pat.