ok i found the cut wire for the optos, some one had at one stage hard wired the 12volt wires to the opto board on the ball trough. then they had cut the wires off.
when i inspected the opto board i found 5 of the 7 leds missing and when i powered it up only 1 of the 2 leds left worked so i removed the faulty led an fitted 6 new opto leds fitted a new plug and socket and all 7 optos in the ball trough register in the switch test.

i also have found part of the mech that drops the top drop target either missing or broken so i will inspect bretts to see what part is missing and then see if i can buy or make one.

more work tomorrow.