"I think what Arthur is referring to is things like loop loss, resistance, shorts etc. "
Yes, what I was referring to, and trying not to be too sarcastic or obvious, is that trouble shooting electrical wiring is an art and a science. One cannot expect others, separated by distance, to help find the fault. It is a personal task.
When I used to teach telephony, and specifically trouble-shooting, the first thing I would ask the new class of students was "When you go to the doctor, regardless of your complaint, what are the very first things he does when examining you?"
SOMETIMES the answers were consistent. "Remove extraneous garments. Take my temperature. Take my blood pressure. Take my height and weight. Measure my blood sugar and 02 levels." From that beginning, I would attempt to draw an analogy to trouble shooting.
Remove equipment and source from pair.
Use a meter and check for metallic faults. Isolate portions of the pair that do not exhibit faults.
Use more sophisticated equipment to find more sophisticated faults. You need a "brown meter," an open meter, a Dynatel fault meter, a Hot Set, and a good tone injector/probe combination. A tool box equipped with test leads that have lots of connectors for various terminal blocks is essential.
Example: A corroded open will show up on an "open meter" as an unbalanced pair. That will cause static.
A combination of intelligence, experience, a mental visualization of the infrastructure, proper tools and a scientific approach will always lead to a satisfactory conclusion.
As an old foreman used to say "It's only battery and ground."