blow/brush the dust off everything. Look over the board for anything blown, busted or cracked. Check for cracks in the boards, or the solder for each connection. Gently unplug and reseat all the connectors, the neckboard, the shatterhook from the anode cup, and check for corrosion. Meter any external stepdown or isolation transformers without the monitor plugged into them. You'd want to meter the HOT, i reckon but i'm not sure how to do that off the top of my head.
If everything looks good, fire one up, and listen to it work. If anything explodes, power down
If all you get is a single vertical line, power down immediately before something else blows.