I have had FIVE sets of z5500s since I bought the first set 6 years ago. One set went bad, returned it, for replacement. Then after the warranty ran out, I unfortunately bought a new set, and that one went, then another, then another then Logitech had to refund my money for the lemon clause. I got all my money back, but still have the old set that had gone bad after the warranty ran out. I wondered if there had ever been a fix found for the low humming noises from both the bass and the speakers. (All 5 sets had the exact same problem in them) The middle stopped completely, the rears and the fronts had a low humming noise as well. The sloburn fuse never went bad and is still intact. It would be nice to get them to work again. They are GREAT speakers, when they work. Not a good thing to say about speakers at all. So, it is not the fuse. I think it may be the control pod though. Mine is a R526 so I would need a R636 or lower to replace it with. I am not sure why though. Why aren't they all the same anyway? Of course, why can't Logitech make speakers that don't have the same issues the entire time they had been on the market? $400 for speakers and these issues NEVER went away. Nice.
And BTW, I have a set of Monsoon(!) 5.1 speakers that are about 12, TWELVE, years old that still work fine and are hooked up right now and working like a champ. Guess I should have never ever bought the Logitech's in the first place.