WOW! i cant believe Crown told you that! that sucks! they built them for JBL... the amp is just simply a CE2000 in a different box.
Your next step is to just find the nearest "authorized" service center... see if they'll fix it? i know my local QSC guy is authorized Crown aswell... and he would fix one for me!
Update...Crown has told me they do not and cannot work on the JBL MP418SP amp modules. They informed me they do not stock the parts for it nor do they have the ability and JBL must service it even thought it is Crown technology.
Bummer. The JBL service centers near me say it can be anywhere from $250-$600 to save just one from this type of blow up.