When [Thomas] showed his 1960s-era Tektronix 545A oscilloscope in a recent video, it made us both nostalgic and happy. Nostalgic because we miss the days when our oscilloscopes were “mainframes” that could take plug-in modules. Happy because we noticed the two handles on top to manage hauling the almost 70 pounds of tubes, transformers, and glass around if you didn’t have the requisite cart.Not only did old scopes have plugins so you could reconfigure them, but there were also handy plugins and racks that could power them so you could build different test setups easily. This scope was an early version of that idea, but it only accepted a vertical section plugin. The mainframe part of the scope has 75 tubes, and the plugin, a type D, has six tubes, too. The power consumption was about 500 watts!If you’ve used a scope like this before, you’ll probably remember a lot of the oddities mentioned in the video. If not, you’ll gain a new appreciation for your modern, sophisticated, and lightweight scope. Of course, the old boat anchor wasn’t working. Apparently, these scopes had ceramic points that didn’t like regular solder, so there was a spool of silver solder inside the unit for repairs.[Thomas] made a lot of progress, although it still needs work to get it working perfectly. We have no doubt he’ll get it working in time. Even the graticule on these old scopes was an issue.