For those with electric flaps on a F model, could use some troubleshooting help. My 75 F has the slider flaps lever. It has detects for the 15° and 33° positions.   This morning while doing the pre-flight, I extend the flaps and when I went to retract them, they stayed down. I slid the lever up and down a few times and they finally retracted. I was not able to reproduce the problem. When I went to takeoff,  I extended the flaps and they went down to the correct position. I tried to retra