well, I've just finished rewinding about 25 pickups (which took about a week!). First I tested the output of each with a screwdriver against the magnet and marked the quiet ones. Then removed one side of the connecting wire (very difficult!) and tested with a multimeter for resistance. If there was infinite resistance (which there frequently was) the pickup came off to be rewound. I used the battery drill and wound off the old wire, reconnected and wound it back on. The break was always right against the body of the pickup. This rhodes must have been in a pretty rough place, climate-wise to be so bad! Anyway, will connect them up tonight and let you know the results.