Quoted from PhilGreg:Lights go dim in the room each time I hit the flippers - they do too with the Surf Champ next to it, but much less.
Then I also suspect a bad power supply in your home.
Large currents do cause a voltage drop, but should never happen when hitting flippers.
Regarding the strong flippers: you should measure 43V on the coil itself. If that's correct also the power supply is ok.