Fibre optic lighting
There had also been several false starts "ping"😠, and mods to the resistor values.
Hence the jeweller's eyeglass to check for shorts.
When it all worked I didn't feel like risking a tidy up in case it then stopped!
I've since learned to jack up the iron temp to 350°C and work faster!!
Main thing, it proved the circuit and current drain, ca 45mA. QED 😊
Gotta rush now - dinner invitation 😋😉
CU later 😎