Apogee Acoustics repair Is it a waste of money to rebuild a pair of Duetta Signature's

I just read your post and wanted to comment. Rich, Owner of True Sound Works, has been restoring Apogees for many years now. He is who I call a perfectionist. The Duetta’s are amazing sounding speakers if you invest in the right amplifier to drive them.
My suggestion is to reach out via telephone to Rich (# on his website). My Dad owns a pair of Apogee’s that are currently having issues and he is going over to Nevada next week for a visit. So, yes, True Sound Works is still going strong. I also have a pair of the small, but mighty pair of Stages that had to be fixed by TSW many years ago. They still sound great today.
Lastly, as a warning, it is rather easy to catch the Apogee bug. Although the original Apogee company has not been around for a long time- their speaker line was quite amazing- including the Duetta’s. Rich probably has a few restored pairs you could listen to to give you a better idea of what yours could sound like after restoration?
Best of luck whatever direction you choose to go.

Imo, it depends on whether these are your passion, your dream, your primary speakers, or a for fun project. If the love affair with them is strong enough, and you are wiling to accept whatever the performance is, then have fun with it. 

I had Apogee Caliper speakers that I bought used a while back. I thought I was genius for pursuing them. I don't think I had them six months; complete waste, and the sound was not all that. Like trying to drive a brick, pretty bad. So, be prepared to have to hassle with amps if you want the experience. Historically, this is an iconic speaker, but it's been superseded by such as the King Sound King III, which I reviewed and own. If you must have that experience, I concur with clio99, and you would be best served to look at the Analysis Audio speakers. 

Beware falling in love with vintage and ancient tech. It'll cost you, potentially big time. I just did a budget restoration of the Ohm Walsh Model F, and I did it correctly, imo. Low budget (under $400), get it working. Very happy I did not dump big money into it, especially since I have speakers that outperform. It wouldn't be too fun for you to push for a redo, then realize over time that they simply can't do what is imagined. That is a definite possibility, so try not to get caught up in the love affair, nostalgia. Nostalgia kills performance. 

I had Diva's built by TSW and they are terrific . Spendy maybe but you would need to spend 2-3 times more to get a better speaker. Need a good amp to drive them.

I had considered rebuilding Apogee Duettas at one time and if they are still around True Sound Works will do a great job rebuilding the speakers, but it will cost you plenty. I eventually ended up with Analysis Audio speakers.