I’ve finally started getting back into printing. I had a bunch of filament feed issues, and it was a combination of a loose hobbed gear, and the set screw part of one of the extruder drive gears started to fail.
Fortunately, I had enough stability left to print a few spares (in addition to the 4 I had in reserve, just in case). I got everything going again, printed a few things, and was printing during the scope repair.
This was a new failure mode, but not completely unexpected. I’m not certain if it was just a bad gear, or if the Skin plugin I was experimenting with was causing the gear to be loaded more than usual.
The automatic extruder fan seems to be working though. I’ll video it next time I have the printer repaired.