Pinging Springs

This came up in my blog feed this morning:

https://hackaday.com/2025/07/11/listen-to-the-sound-of-the-crystals/

I've never messed around with quartz, but it's a whole new set of regulation equipment. This seems a lot like the iphone style regulation apps that a lot of people use. Cheap to free ...

I serviced a movement here recently, and want to get a gut check on my diagnosis. It's an old (50s) movement with quite a few variants. The mainspring needed to be replaced, and I found several specs listed. The variation I have has a higher jewel count than I've seen listed among the variants, but ...