B & W 805 nautilus broken tweeters ?


Does it happend to any of you guys ? I have a pairs of b & w 805 nautilus recently purchased from a local guy but after a month of listening to it I just realized that no sound coming out of the tweeters that all , sound like both broken tweeters or something wrong with the crossover , I have no idea ! Please someone with experience with diy can give me some idea or input about this , does it easy to burn the tweeters or crossover ?
atl4love