Spent a few hours today on Conti. Thought it was over due for cleaning of wiper boards and wipers. Conti wasn't played for years prior to finding its way to my collection. Business card and contact cleaner wasn't going to clean these wipers. They were dirty bad.
One at a time pulled wipers and cleaned. Then gave wiper boards a good cleaning and slight dose of 3 in 1.
What I found out afterwards was that the wiper mounting holes allow enough adjustment to cover two columns of contacts. Luckily only two of the 4 were installed lined up on the wrong column of contacts. This made realizing problem easier. So if your slot isn't paying correct or not at all on certain pays, this maybe another thing to check.
Jim