Hi all I have a SB220 that has not had juice put to it in around twenty years. I had the house wired for 240 volts (around there) and would like to put the amp back in service. What precautions should I go through for powering it up. It is completely stock with no mods. Also do I need to put a keying setup in between it and my IC706mkllg? Thanks and 73 guy wr7k