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NJ1's picture
Last seen: Never ago
Joined: May 19 2008 - 7:38am
repairing old Bertagni SM300 piezo tweeter

I got for almost-free a set of Bertagni SM300 flat panel speakers. They pretty much rule, as many may know they're 4-way speakers made of huge polystyrene panels and they sound great, but the HF driver in each is a little piezo(?) tweeter, and one of them is not working.

I hooked up another tweeter (of a different design) in parallel briefly and got sound, so it's gotta be the tweeter itself, nothing is wrong in the crossover etc.

Any idea where/how I would source something like this? Any chance I could try to fix the actual tweeter myself if I can't source a part, and if so how would I do this? bear in mind the new one has to be able to be glued to the styrene LF driver (see pix).

Weird, I know.

any slight lead or direction anyone can steer me in would be great, tests to perform, measurements to take, etc. There seems to be continuity and very low resistance between the two leads on both the working and non-working transducers. Poking around with my meter, I can't find anything obviously different between the working and non-working tweeters. Of course I did not disconnect them from the circuit so my measurements are probably meaningless.

It seems almost like there's a little piezo transducer attached to the cone some kind of way. I'd happily replace that little piezo element if (a) I knew what to replace it with, exactly and (b) how to get it off.

Oh, here's a pic of the speaks in case yr interested.

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