This seemed to solve the problem until a few months later when the customer started to complain again. Retesting the pairs found the original pair was quieter. The cable was tested with a TDR and an unrecorded splice was found. Close examination of the splice showed it to be to ally saturated with water. The cable was re-spliced and the lines were quiet.
Splits can be hard to find because they cause such a slight change in pair impedance.
The Model 1205T can greatly help the craftperson find splits by using the crosstalk mode of the instrument. Simply connect tip and ring of one of the split pairs to Line 1 and tip and ring of the other split pair to Line 2 and put the 1205T in the crosstalk mode. The point of split will easily be seen on the waveform display.