That small "bulge" is likely a ferriod RF filter (a magnet type device), thus is not really the problem. It is likely that a wire has broken at or near the filter, a relatively common occurance. I recommend to just replace the cable, as this is not really a user servicable problem, unless you feel comfortable tracing down the broken lead with an ohm's meter, then resplicing the wire, assuming it did not actually break inside or directly at the filter.
Robert Richmond