Eelevator is right about there not being volatile memory on a TAC20. If your parameters are lost it wasn’t because of the battery. FSH2 is the off position monitor for the phase 1 switch so should be on and FSH1 should be off. It sounds to me like your bottom directional limit is set too far down. The learn will fail if that’s the case. It should be 1” to 1-1/2” below the floor. With the car level at the bottom floor, mark the bottom of the selector on the tape the. Set the top of that magnet 5/8” below the mark. With IMS on 8 bit ports and positive logic and the car level at the bottom floor you should have every IO high in port 3 except NTSB.
