The midrange driver on one of my B&W 802 stop moving. i listed it at ebay but decided to pull it out and make it a project to fix it.   Madisound suggest replacing the capacitor which i did and to my surprise,  it did work and it sounds damn good.   now i am in a process of replacing all the capacitors since they are about 30+ y/o (the bad speaker first to compare the sound between original and modified).   i am installing different brands of capacitor (mostly poly cap some electrolitic) to match the value and fit the tight space.  I bought some Mundorf Supreme and Clarity Cap for the tweeter and midrange section and will install them soon.     
The base is a little louder with the new capacitors.  hopefully they will balance out once i replace the capacitors in the tweeter and midrange area.  
Any other suggestions?  
i also uncouple the 6 diodes to eliminate the protective circuitry.  
These are my speakers, they are 32 y/o 
  
Crossover at the bottom of the speakers, tight space 
 
replace electrolitic capacitors 
 
disconnecting the diodes 
 
disconnecting the diodes