Spotting Index (bingo)
The spotting index assembly is mounted on the back door just
to the right of the spotting disk. It consists of a coil, some
switches, and an arm. In it's inactive state, the arm is engaged
on a tooth on the spotting ratchet, and it stops the spotting
wipers from turning. When the coil is activated, the arm moved
away and releases the spotting wipers.
