A-Line, this is truly a case where a picture is worth thousands of words.
At $1000, it's far from cheap. Yet, I've had to try to run down the exact type of fault you describe a number of times, using everything from a dowsing rod to a minesweeper, without a great deal of success. One of the major problems has been false paths - getting a strong tone where there are no wires.
This also seems an ideal candidate for tool rental companoes to offer .... does anyone have that option where they live?
