Kurzweil piano keys are clicking seems to be worn out.

On our church's Kurzweil grand piano, some of the key feel like the weights are messed up. Some make a clicking noise when you mash them and they weight of the key doesn't feel right. The keys that are affected are in the middle section of the keyboard so I feel that something is worn out. I've worked on regular piano before but I haven't attempted to look inside of this one. Is this something that an ameteur could fix?