> Being that this was 1971, it was probably more straightforward to repair the botched installation/repair rather than do the whole PCB over from scratch As an

> Being that this was 1971, it was probably more straightforward to repair the botched installation/repair rather than do the whole PCB over from scratch As an extra data point I did a contracting gig in early '90s that involved building a diagnostic system for a specialised analogue circuit board that was used in the oil industry. The boards were held in place and an automated probe system took measurements at numerous places. A constraint satisfaction algorithm then modelled failing components in an attempt to match the faulty readings, and thus locate the failed component(s). The algorithm came from a three-year Ph.D project funded by the company concerned, and I was part of a team of five that were implementing it over a six-month period. This was considered a small price by the company, compared with the cost of throwing away a specialised board manufactured in small production runs to high tolerances. The probing system already existed, and was used by electronics experts who were attempting to perform the same diagnostic process using their own (expensive) skill and judgement.