The bright side is that it.s all better than before, so I.m still happy, even if, righfully so, Clive disagrees with my so called ˇˇall okˇˇ opinion. I.ll rephrase that. All better than before.
Perhaps we have a difference in language. By "working OK" I meant that are the inputs now working as intended , ie if you connect one of the inputs to ground does this show that it is triggered in Mach3 ?

For the avoidance of doubt when we ask for a voltage measurement between an input and ground we mean between the input pin and -ve of the power supply (not earth star point).

Do you get the tingle sensation when you touch the star ground point.