Kef 103/4 One Speaker Scratchy Sounding?

I picked up a nice pair of these a year ago for almost nothing. When I got them home I noticed one speaker had what sounds like a bad tweeter. I would like to buy a tweeter for these if that's what the problem is. I push in on the cone and the scratchiness subsides. I am talking about the reflex driver as far a pushing in the outer cone. These speakers do sound great. And I am tired of not doing anything about this. Any insight would be greatly appreciated. I have read that the tweeters in these can be quite sensitive. Thanks.