Well, so much for the easy fix.
When you inscribed: "The neon light that illuminates indicating a good ground is not lighting up anymore". Which of the 3 lamps are you referring to?
I would guess(tm) that this is what you found inside:
It's not a high brightness NE-2H or NE-2UH lamp.
Neon lamps have a V/I curve with hysteresis. They turn on at about
65VAC, and stay turned on until the voltage drops below about 50VAC (maintaining voltage). The actual voltages are not very well controlled and are affected by ambient lighting, radiation, and temperature. In between these two points, the neon lamp exhibits negative resistance, which makes a dandy relaxation oscillator or logic circuit.Drivel: I'm reading from the "GE Glow Lamp Manual" 2nd edition 1966. GE never made an NE-2. The closest equivalent is their 3AG lamp). (12.1MB)