replaced the opto transmitter with one from jaycar and it's now working   

checked the coil and it's the correct one, found a screw loose that holds the left ramp under the left popper, tighten it up and now the ball bounce off the ramp and back down the popper maybe once every ten times instead of on most occasions
how do I check to see if I have the correct spring installed ?

anyway it's time to get back to saving earth again from those martians, lol