I think the switch error report stays active until the cpu senses that switch activate.

Also I think as well as the always closed switch, the opto switches should show up as closed and then change to open when they are activated (I.E oppsite to the normal microswitch)

Ok Steve .. It makes sense that opto switches should read normally closed (DOH hadn't thought of that) .
I started a game and put the ball in the playground hole to activate switch but when I turned off /on the switch 34 error still comes up in self test .
Also I have realised that both poppers (switch 34 and 37) activate several times when you 1st start a game .. I had heard something but kept thinking it was the ball shooter .
So , at least whatever is wrong is consistent and related to opto switches it seems . Thanks to a reply from JPD (Jeff) on AA , I know understand that the second popper (or VUK) looks after both the snack bar hole and Tailight Park . When I put the ball in the hole there I saw it roll down to the VUK at switch 37 and sit there till ball search kicked in .

Even though I do have a problem with my new pin at least I am learning a lot about how it works.

Next thing I will try is reseating all connectors related to optos .