My right phurba on my Shadow table will not move to one side. I originally replaced the metal piece which moves back and forth and gets worn out after a while (the hole in the metal will get bigger). I put everything back together and everything worked fine (the phurba was moving to both sides) for a few games. Then the same problem returned. The phurba will move to one side and now will barely move in the other direction. There are 2 coils that work the phurba. Is that where I should start looking next?