It doesn't matter, I've seen burnt to a crisp, nothing but cinders and some wire left fried escs sent back and they get totally replaced at the flat fee. Castle will repair it or replace it completely for that $30 flat fee cost given on the support area. This is not warranty, so it really only matters that you have something to send back (has to be same type esc though).

As fussy as Castle is about their esc, I bet most sent in for repair are tossed in the trash and a new one sent out as replacement.