If you're into old tech, one of the things you need to be aware of is some things were built from kits and may not be of the best quality. This is something to keep in mind when buying sight unseen from places like eBay. There are a lot of "desirable" devices such as pretty much anything with an eye tube - but test equipment of this nature was often wired by the purchaser.

For example, I recently picked up an Olson C-R Analyzer (Capacitor Checker) from a hamfest for $20. It was in physically good condition, but I could open it and saw that it was wired so poorly, it's amazing that it worked. It took a lot of time and wire and some new parts to make this device work again without fear of fire.

I see these same devices on eBay for well over $100 because they're desirable in that they have a meter for leakage testing, and an eye tube for measurements. They look cool, so people price them accordingly. Had I purchased this device for over $100, I'd be very upset that it was in such poor condition, and had tried to use it long term, I could have wound up with some damage to property or myself.

What's the moral of the story? Know what you're buying - especially when it comes to old stuff. If you can't see the inside and you suspect it's a kit build, stay away unless you absolutely need it.

I wrote some posts about this very thing and my adventures in making one work, you can check that out here: https://wereboar.com/projects/index.php/2024/12/28/an-olson-te-189-c-r-analyzer-does-it-work-and-final-thoughts/