All of a sudden my DRSSTC Tesla coil stopped working.

It took a long exposure in a darkened room to see the very faint corona around the top of the primary coil – that’s definitely not right.

Ooh that's not good

The coupling between the secondary and primary coils was too tight. So I rewrapped the primary coil tighter and lower than it was before, and that seemed to fix things.

Not sure why that suddenly started to happen, as it’s been working great for about a year.