These things always seem to happen on weekends, don’t they. OK Frank, take a breath. Assuming you haven’t already heard from your Dealer how about back to basics.
Power off (front switch) and remove the power cords from the Fathoms. Switch the Master Slave switch on each unit Slave becomes Master. Check the grounding switch to make sure it isn’t between positions. Now connect the Fathoms so that the Slave unit is now the Master and vice-versa. Reconnect the power cord but go directly to the wall outlet, not the Power Conditioner. Try to power up just the Master sub (used to be the Slave) first. If you get lights, use the demo button on the new Master sub. If no lights and they are still dead, I’m afraid you are in for repair or replacement.
Power spikes can damage any electronics.