and yes, it proved to be induction from the long flat cables where stepper & endstop were in the same sleeves.
I tore off the endstop pair, twisted it many times, about 1 turn per 2cm , both in the 1m extension cables & the original , shorter cables. - still in the same sleeves, works perfectly low.
I tore off the endstop pair, twisted it many times, about 1 turn per 2cm , both in the 1m extension cables & the original , shorter cables. - still in the same sleeves, works perfectly low.