I bought a damaged typhoon h plus on ebay, repaired broken leg and cleaned it out. it had crashed in the water. It had an uncharged battery which I charged. Now it won't turn on which I half expected. Main board appears fine w/ no obvious damage. Now the ?. Is there anyone who can repair this board. I know if I send it to most repair shops they will just want to put in a new board which will cost plenty. Another possibility is if I can't get board repaired is to change it out to a H520. From what I can see from looking at pics, the mounting screws look to be in the same place. The motors should swap OK, same battery and other components. Thanx