Thanks for the video Dave, and keep on the excellent work!
I had a issue with oscilloscope ground many years ago.
I have bought a regulated power supply 30 V, 3 A, linear regulator, nice big transformer.
So everything should have been well isolated...
I found out the hard way as I had to put the ground of my probe to the V+ line one day, and bang, the power supply was shorted.
Luckily the current limit was set quiet low, so nothing catastrophic happend.
But of course it was enough to scare a "young player ...
)
And what has caused the problem? The power supply has a case of sheet metal, and the wire that goes to the - Terminal was by accident squeezed between 2 pieces of the sheet metal when it was assembled and the isolation was damaged.
So the - Terminal was grounded, causing the short over the ground connection.
After isolating the wire and taking care that it was not squeezed again the power supply still serves it's duty.
Dieter