You need this for the adjustable cup on the non-drive side of the bottom bracket.

Park Tool Co. » SPA-1 : Pin Spanner: Green : Bottom Bracket

You first have to remove the lock ring, which can be difficult. Park tool makes a spanner that doesn't work all that well, there are a couple of threads on that. I loosen the lock ring with a few taps of a hammer and metal punch then use the Park spanner to finish the job. You should be able to remove the bottom bracket then and see whats going on. Years ago, on a different brand bottom bracket with caged bearings, the cage got chewed up and made a god awful racket. Maybe that is what's broken on yours.

The older Campy bottom brackets are generally long-lasting, but require regular maintenance, especially as they are more susceptible to water, dirt, etc, that can get inside the BB shell.