Same prob with me the other day too. Lost first and fourth, then got first back and lost third. Then lost all except 2nd. Go figure, anyways, heaps of metal in box caused from moisture inside it somewhere. Prob from sitting in Japan, slight signs of rust on the tin where it should of been shiny. $2.5K to recondition, but I rang around and fluked a 2/h unit they guaranteed to work. Fitted it and its all good now. Defintely did not fit it myself, I would rather change the motor "again" before I attempt that. Now I have got a spare motor and box. Both needing a recond. One day they'll get the attention they need.