Subwoofer Not Working?
 

My brother visited today and showed me his system. He has 2 Power Teknique 15's dual 4 ohm voice coil subs. They're about 5 or 6 years old.

I showed him how to wire them in parallel and stuff to get lower ohms, and they worked great.

One stopped working after some use. We don't think it's blown, because it doesn't smell, and the cone moves smoothly when pushed in. When we try to hook it up, in various ways (we've tried each coil individually, etc) it just doesn't move at all and makes no sound.

Any suggestions or ideas as to why this would be happening? Can subs just out from old age?

I just checked both coils with my multimeter and they show no continuity at all, is this what blown subs show?

blown shows 0 continuity...however check your tinsel leads near the cone, They could be burnt.

Tinsel leads? Just where the wire meets the cone?

yes, those are set with enough flex to move with the cone
http://i51.photobucket.com/albums/f392/Raven21633/Antique%20Radio/Silvertone/Silvertone_3004_25.jpg

The voice coil coil also show an open circuit if it was overheated fo an extended period.
The woofer can be rebuilt as long as the cone is ok, but usually cheaper to get another.(a classic is an exception to that thought for some)

Well, they are still connected to the cone. Is there anything else I can do?

Yes, check them with a Multimeter near the cone, when they are burnt, they are intact just not making a connection.