On Mon, 6 Nov 2017 10:01:55 -0800, "David Farber"
wrote:

Jeff Liebermann wrote:
On Sun, 5 Nov 2017 22:36:43 -0800, "David Farber"
wrote:

I have one of those polarity/line/ground checker plugs. It has three
lamps that illuminate according to the condition of the 120VAC
outlet. The neon light that illuminates indicating a good ground is
not lighting up anymore. Will this replacement neon light work
properly for this application?

https://www.digikey.com/product-deta...C2A-ND/3150384
There is a 68k resistor in series with the lamp. What does the
breakdown voltage indicate?
http://www.vcclite.com/_pdf/Neon%20I...amps_7_&_8.pdf

A picture of a similar tester is here.
http://www.acehardware.com/product/i...ductId=3099752

The common NE-2 neon lamp will work just fine. I've never bothered to
tear one apart so I don't know what's inside. Looks like there are
different design schemes:
http://www.giangrandi.ch/electronics/neon/simple.html
http://www.electro-tech-online.com/threads/information-about-electric-tester-circuit.132363/#post-1104807
http://www.marcspages.co.uk/pq/4511.htm
http://www.electro-tech-online.com/attachments/sch-1a-png.87460/

I doubt that the NE-2 lamp is the problem. My guess(tm) is something
fell apart or came loose inside. Probably a bad crimp.

Hi Jeff,

I opened it up and the crimps and resistors are good. Do you have any idea
what the lamp's breakdown voltage specification indicates? According to the
datasheet, the NE-2 has a breakdown voltage of 65VAC. The high brightness
bulbs have a higher breakdown voltage of 95VAC.

Thanks for your reply.

You do know that only 2 of the three bulbs should be lit for a good
outlet, right? The ones going from hot to ground and hot to neutral
should be on. The one going from neutral to ground is always off
unless hot and neutral have been swapped due to a wiring mistake.