Oh no, no disassembly. The interior of the amplifier is potted / sealed so you would not be able to get to the components. I would use the long and slightly bent pick tool and insert it between the centre captive pin and the inside wall of the barrel of the BNC connector where there is a slit in the centre captive pin then try to rest the pointy end of the tool on a portion of the broken pin and pull it forward / out. That broken centre pin will have a small edge / lip between the back where the wire used to be soldered or crimped and the actual pin itself.
I know, it's hard to explain / visualize.