I just purchased the American Flyer 771 Stockyard and the cattle won't go up the ramp to the box car. They just pile up at the bottom of the ramp. They go around the pen just fine and the pads look good on most of the cows. I tried everything from adjusting the vibrating coil to adjusting the voltage. I also have replaced some of the pads on a few of the cows, using the suggested Shur-line painters pads, cutting them as instructed. I think I must have cut about 20 pads at all different angles. The mat looks new and appears to be installed properly. I have spent hours and tried everything I could think of and everything that was suggested on line. Any help I can get would be greatly appreciated.