The garage door is half chain, half wire drive. The wire broke last week. Instead of replacing the whole thing, we spliced wire to the old wire. We finished the work, plugged it in and pushed the wall mount button. The garage door will move about a foot and a half, and then go back. We have adjusted the tension, opened the case, there wasn't any shavings. Everything looks normal and greased. We have been working for the last 5 hours and have no idea what is wrong. Any ideas?