I have a Computer Trak 100 monitor hooked to an 8 row 7200 planter and would like to know what the best way to test it to make sure all sensors are working. The lights all come on when I power it up but I cannot get them to turn off or flicker when I drop seeds through the tubes. I saw that all of the red sensor lights were on when I plugged in the planter harness. I’ve tried switching between HI/LOW and also adjusted the tuning knob but the lights for all rows stay on. Let know your thoughts.