At one time, filecat13 had some PC600 parts. I have spare 904ti, but that won't help you. I'd pull that driver out and give a good look-see, it might be simpler to fix than you think. Might just be something pushed out of alignment. In any case you could run the thing with one driver disconnected for a while. I just can't think of anything in the actual motor that pushing on it would harm, unless it was being run while he was pushing on it and the coil got dinged. Lesson: don't run them naked with toddlers around.
It was on at the time (Shrek) Something is now rubbing. I disconnected it and because it's a sealed unit it still moves as the pressure changes from the other drivers and you can still hear it, but not as bad or as often. If I take it out you don't hear it, but there is a big hole and it's not right. I'll do some more experimenting this weekend to find a workaround until I can hopefully find one. Time to start daily e-bay searches I guess. I already PM'd a guy that had a complete 5.1 setup on e-bay that got no bids. He wanted $1,500 for all 7 speakers. Where was he 3 years ago!