Even after AMF put them out, there were a lot of lanes with semi- automatic setters. You had to scramble to set three lanes. You first grabbed the ball and put it on the return ramp, then hustled to get all the loose pins out of the pit (or off the deck) and thrown into the pinsetter rack. They had semi-circular 'hoes' to pull pins out of the gutters when they didn't fall into the pit.
When the frame was over, you finished filling the rack, and manually actuated the setter to put them down. It was electric, but only for lowering and raising. You still had to manually throw all the pins into the setting holes.
The whole deal was to get it all done before the ball made it back to the line. A good 'monkey' could set three lanes, and make $15-20 a 4-hour night back in the 1960s. (that was a chunk of change, then).
This was after the time when pins were manually set on spikes that raised up out of the deck.
I bought my first car by setting pins at the local college's eight lane bowling alley. You got tips if you worked fast!