Need Help Troubleshooting Polk 7

I have a pair of early Polk 7s: Peerless tweeters, single fuses on back. One of the speakers works flawlessly. But the other one exhibits an irregular break-up of high frequencies. Seems like it needs a certain combo of freq and volume to occur. It's not a drop out of sound, but more like a raspy sound or distortion in audio quality.
It's hard to replicate, but something is not right. Sometimes I find myself thinking it healed itself, only to find that it reappears. I've switched channels, tried diff amps, and different sources.
Just looking for some thoughts on where to look, or what it might be. I was first going to clean the connections at the binding posts, fuses, and drivers. Anything else to check/clean?
I always thought these Peerless tweeters either worked or they didn't. Is it possible it could be an internal problem with the tweeter?
Thanks, in advance, for any suggestions!
It's hard to replicate, but something is not right. Sometimes I find myself thinking it healed itself, only to find that it reappears. I've switched channels, tried diff amps, and different sources.
Just looking for some thoughts on where to look, or what it might be. I was first going to clean the connections at the binding posts, fuses, and drivers. Anything else to check/clean?
I always thought these Peerless tweeters either worked or they didn't. Is it possible it could be an internal problem with the tweeter?
Thanks, in advance, for any suggestions!
Comments
I bet the wire is corroded at the fuse block as well
To clean the fuseholders and other connections, 2000 grit paper works well. Or did I use 3000? Either one is fine.
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