What is the best way to fix a wire wrapped backplane? I have a pdp-11/40 with a short to ground in one of the backplane runs. I probed the backplane with a wooden stick and with some wire tyes and the short went away. I have a pretty good idea which segment of wire is the problem. I have probed the area again and I can't get it to come back. So, what should I do? 1. Be happy it is working. Note the problem in my log book. Wait for it to happen again. 2. Replace that run in the backplane. I figure I will have to replace most of the run because this segment is on the lowest wrap level and in the middle of the run, so I have to replace this one and the ones on either side. I have done some wire wrapping, but this thing is very intimidating. Replacing the wire is easy, but I am afraid that taking out the old ones will create another problem. These backplanes have the wires pretty taught and they are pulled over square edged pins. How fragile is the backplane wiring? If you have a PDP-11/40 then the KM11 is your friend. I have been troubleshooting this problem for a while, but after I handbuild a KM11 (from Tony Duell's notes), the problem was obvious.