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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 10th Feb 2021, 9:59 am   #1
jonnybear
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Default Neon EHT Indicator wand.

Neon Indicator wand useful item, quick checking for eht, lcd backlight inverter safely, all you need is a 5mm dowel I used a lolly stick neon bulb and a piece of shrink sleeve,
cut a angle with junior hacksaw fit neon in groove and finish with shrink sleeve.
Keep in pencil drawer one day it may be useful.
John
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Old 10th Feb 2021, 11:17 am   #2
Julesomega
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Default Re: Neon EHT Indicator wand.

In principle fine, but don't try it on the mains
Wouldn't it be worth adding a 220k resistor in series, it will still light up nice and bright with EHT
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Old 10th Feb 2021, 12:13 pm   #3
jonnybear
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Default Re: Neon EHT Indicator wand.

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Originally Posted by Julesomega View Post
In principle fine, but don't try it on the mains
Wouldn't it be worth adding a 220k resistor in series, it will still light up nice and bright with EHT
It will not work on the mains as it is totally isolated no path to earth, fitting a 220k resistor would make it dangerous giving it a path to earth via your body, not good when prodding around eht items. the neon lights on proximity.
John
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Old 10th Feb 2021, 12:19 pm   #4
factory
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Default Re: Neon EHT Indicator wand.

This was a technique recommended in older Tek oscilloscope manuals for checking the high voltage oscillator was running, the neon was placed against the glass envelope of the oscillator valve, though in the picture it is held without a stick.
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Old 10th Feb 2021, 12:36 pm   #5
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Default Re: Neon EHT Indicator wand.

Had one in my tool kit, well worth it for checking around the EHT in TV sets.
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Old 10th Feb 2021, 12:41 pm   #6
jonnybear
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Default Re: Neon EHT Indicator wand.

I know it is an old technique, I was just using odds and ends lying around, I used it to detect if inverter was working on laptop, did not fancy holding neon by the wires, seeing what happened to an apprentice years ago when he stuck a neon screwdriver into a insectocuter to check it was working, his reaction showed everyone in the room it was.
John
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Old 10th Feb 2021, 12:47 pm   #7
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Default Re: Neon EHT Indicator wand.

You're saying it works on DC?
Intriguing, what sort of minimum voltage do you need to light a disconnected neon?
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Old 10th Feb 2021, 12:47 pm   #8
Dave Moll
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Default Re: Neon EHT Indicator wand.

Quote:
Originally Posted by jonnybear View Post
...did not fancy holding neon by the wires, seeing what happened to an apprentice years ago when he stuck a neon screwdriver into a insectocuter to check it was working, his reaction showed everyone in the room it was.
John
As long as it didn't become an apprenticocuter!
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Old 10th Feb 2021, 3:08 pm   #9
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Default Re: Neon EHT Indicator wand.

I used to have a similar "Dipstick" for testing whether there was RF present in transmitter/ATU 'tank' circuits - mine used a NE-2 type Neon with its legs extended by a couple of inches of wire, fitted into the end of a clear Polystyrene tube about two feet long.

MF/HF power made it glow orangey; VHF gave an impressive purple!
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Old 10th Feb 2021, 3:28 pm   #10
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Default Re: Neon EHT Indicator wand.

I'm sure readers will already know, a simple way to test on a micro wave cooker is to mount a neon with both lead bent outwards (antenna) using some Blue tack and a glass of water. As the plate rotates the neon flashes on and off
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Old 10th Feb 2021, 6:26 pm   #11
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Default Re: Neon EHT Indicator wand.

Used to tape just the glass neon on tip of vhf 2 way radio aerials on my works van. Nice purple glow.
Toy, really, soon fell off and never replaced.
Rob
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Old 10th Feb 2021, 7:04 pm   #12
Dave Moll
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Default Re: Neon EHT Indicator wand.

Surely, a purple glow requires argon. Neon gives an orangy pink.
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Old 10th Feb 2021, 7:28 pm   #13
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Default Re: Neon EHT Indicator wand.

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Originally Posted by Dave Moll View Post
Surely, a purple glow requires argon. Neon gives an orangy pink.
Dig out a decently-powerul VHF transmitter, hook up a dummy-load, dangle your neon glowbottle into its PA and hit transmit.

You'll get purpleness.

Trust me on this.

In times-past the colour-of-glow from your neon-dipstick was a reliable indication of whether the parasitic-oscillations in the amplifier-you-were-debugging were VHF or LF.
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Old 10th Feb 2021, 9:31 pm   #14
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Default Re: Neon EHT Indicator wand.

This looks a fun little project I like gimmicks like this. I remember back in the day it was possible to buy some impressively large neon lamps. The little modern ones do look a bit sad. Thanks for posting.

Regards Chris
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Old 10th Feb 2021, 10:08 pm   #15
Dave Moll
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Default Re: Neon EHT Indicator wand.

Quote:
Originally Posted by G6Tanuki View Post
Dig out a decently-powerul VHF transmitter, hook up a dummy-load, dangle your neon glowbottle into its PA and hit transmit.

You'll get purpleness.

Trust me on this.
Thank you for enlightening me on this.
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