It is doubtful that you would get NO sound from capacitors going bad. You might get no sound from a tweeter or midrange, but in most cases, you would still get sound from a woofer, but, of course, all of this depends upon the exact design of the crossover we are talking about.
If I were to hazard a guess, I would say that most likely you had a bad connection somewhere. In some cases, there are fuses that can be blown, but if my memory is correct, that does not apply to the Pioneer CS-99A.