At a former employer, they threw away a HP 4195A network analyser. The reason was because it had some problems with its internal source. I kept the unit for a few years and always was afraid of opening it and repairing it because I thought the potential to further damage it was too high. But now I tried to repair it and it worked 🙂
A few years ago, I bought a HP 8753C network analyser. The cool thing is: it has options 06 (6 GHz operation) and 02 (time domain). Unfortunately, recently it showed an annoying error message.