The Trough Jam should not be on, and the Trough 1 should be.
With 6 balls in the trough, Trough 1 through 6 are on, I then added one from the shooter lane and the Trough Jam switch activated.
Check the trough holes above the ball about to go to the playfield next for something blocking them (or maybe the hole is missing), or something is wrong with that LED/Opto pair.
Let us know what the issue is when you figure it out.