Also Location Location Location Places were there is big industry for a long time is good. Silicon Valley was excellent but not as much now as most hardware m

Also Location Location Location Places were there is big industry for a long time is good. Silicon Valley was excellent but not as much now as most hardware mfg. is outside now. Also suburbs of industry towns have a good chance. College towns or other concentrations of learning in an area (schools/colleges store their equipment for a long time before remaindering them off). Just think of where the tech was back in the period you are interested in, and check out local offers in that area...