I found a 1914 Cent that looks like someone may have used it to prop up a soldering iron. Lincoln's face seems to have some solder dribble. Using coins for temporary soldering stations was not uncommon back in the day of vacuum tubes, B&W TV, and landlines. At least it wasn't a D! .
I miss the days when components were naked-eye visible and all the circuit traces were out where you could get to them. My soldering gear is very dusty now. On the other hand, I kind of like having all human knowledge in the palm of my hand, so I've made my peace with the tradeoff.
Even so, I think I see a cud at about 1 o'clock on the obverse of your coin. Just saying. Don't know if that is also a product of using the coin as a soldering iron prop.
Yes, when you could mentally physically trace the circuit from tube to tube and, based upon current characteristic, determine what needs fixing.
Good eye La Cointessa, yes that cud looking smash seems to be where the iron spent some time resting.
