DICONNECT IT! if it does not hum when power is applied it is fried and can dammage you pushbutton or ACC control board. If it is not leaking, I would just leave it unplugged and forget it. If you are a pureist, however, a rebuild is not a common option. These are a PITA to replace as I am sure you have figured out. If you do be sure to put a 1 amp fuse in line to prevent burn out of ACC board should it fail again.