Looks like you'll have to access it from the rear maybe remove the black faceplate entirely probably with blind screws from the back. . The ScanSpeak 21W8554 is no longer available anywhere, I did a quick google search on it found a guy on DIY audio offering a pair, very old thread though, but it never hurts to ask.
What most likely is wrong with the driver is that the voice coil leads are broken in the transition from the former to the cone, with some skill you can fix it. Another issue can be a break where the tinsel leads attaches to the voice coil leads on the back of the cone, if this connection is black in color you have your answer, this too can be fixed though.
Best of luck
Peter
What most likely is wrong with the driver is that the voice coil leads are broken in the transition from the former to the cone, with some skill you can fix it. Another issue can be a break where the tinsel leads attaches to the voice coil leads on the back of the cone, if this connection is black in color you have your answer, this too can be fixed though.
Best of luck
Peter