Non-cover plate metallic rattle on Chromatic

Hello Kinya,

I just received an unused but pre-owned Hohner 270 Deluxe. Unfortunately there are very significant metallic rattle/buzz when playing the 4 blow, and 2 draw. I removed the cover plates and the sounds continue unabated. It's not windsaver noise, this sounds very obviously like metal on metal. To be clear, the notes in question do play, but are accompanied by the  relatively loud metallic buzz/rattle, which seems to emanate from the area of the note being played, as opposed to some other part of the harp.  Any thoughts on trouble shooting and repairing would be greatly appreciated.  Thanks,

Loren