A nice piece of equipment, although I might not want to be hanging on a pole testing lines when somebody tried using it.....
Those 90V batteries you mentioned sound very much like the zinc-carbon HT batteries ("B+" battery in U.S. terminology) used in old valve/tube portable radios years ago.
It was most likely corrosion somewhere. Just before the line went out I noticed it getting rather noisy, and a couple of incoming calls had the ringing tripped out on the first ring. The automatic tester was reporting "Rectified loop" as well -- All very typical indications.
The spare pair being right outside was a real stroke of luck. Over the last few years there have been a lot of people moving into houses here which were previously just holiday accommodation, so there's been heavy demand for extra lines, and you'll see a lot of DACS on poles (digital multiplexer to run two lines on one physical pair).
While I was in town a couple of days ago I ran into another of the engineers who's up here temporarily and had a chat with him. Apparently they've had a lot of line problems here with the recent thundery weather and it coincided with many of the local engineers being on holiday, so that's why BT got a few engineers up here from London for a couple of weeks.
The guy I spoke with said he'd never seen so many corroded distribution points before! Right down at ground level the green inside an opened DP up the pole was immediately obvious. All part of the fun of living next to the North Sea!
[This message has been edited by pauluk (edited 08-30-2004).]