trader_4 wrote, on Thu, 01 Jan 2015 06:41:52 -0800:

So, if that's right, then the question remains, what failed in Danny's
detector? There have been so many posts, I'm unsure of is what exactly
he measured, what the readings were, etc.
I think he measured that there was infinite resistance between rod and
furnace metal, ie no shorting of the insulator. I think he verified
conductivity from end of wire to tip of rod, but not sure what exactly he
measured there. So, I don't understand what could be wrong with the old
one......

All this is true.

I'm "guessing" that a crack developed in the ceramic that allowed electrons
to flow both ways to the metal chassis that the assembly was bolted to.

But that's just a guess.