The pin I purchased had been left for years in a garage without playong. The motor relay was out as well as the diverter mechanism.
Today I have removed, the apron ans all balls. In test mode I only get the 3 expected closed switches : ball diverter, trap 1 and trap 2.
Adding the first ball gives an extra display : through 1, a second ball through 2, the third ball through 3
I have repetedly done the following, so about 40 to 50 balls in total were ejected:
I started a game and played all balls
Then I hit the targets to open the traps and put one ball in the left one. And checked what happened with the next ball ejected. Only one ball was ejected.
I did the same with the right trap. No problem either.
I have not observed any wrong behavious of the through.
I have reseated the apron, played a few balls, the problem appeared once again. No ball was in a trap. Forgot to make a switch test. I ll do it next time, and will come back