i cant see how anything could damage your chassis like the way you described,the only way you could damage your chassis from the signal in is having some sort of voltage surge,but that would never affect your lopti.i think you have just been unlucky-where is the spark coming from on your lopti,if its underneath then prob just a dry joint,if its from the lopti body then you could try putting a bit of plastic cement in the hole-otherwise a new lopti is required,might have to look at a few caps as well.