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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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4th Dec 2019, 12:55 am | #41 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
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Re: Neon Tester Screwdrivers
I am slightly puzzled that i haven't ever seen any upgrades to the basic Neon Tester design. I was browsing on an IET forum earlier and saw that several bods had had similar thoughts, viz:
-Two (or perhaps even three) resistors of equal value in series, mitigating the effect of a resistor failing s/c (a rather unlikely failure) This would make the tool bulkier, but it could still be acceptably small- especially compared to a voltpen. - All the internal components potted in clear resin to exclude (as much as possible) accidental water ingress. Would this increase the energy of the shrapnel in the event of a explosive failure of the tester though..? Heading away from electrics towards ballistics here. I can't really accept that the proliferation of 'better' testers would have halted development to the point where no-one took the opportunity to develop and improve. ....Or are there hidden consequences to the improvements i have suggested? Dave |
7th Dec 2019, 5:01 am | #42 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: Neon Tester Screwdrivers
I think I've seen 2 resistors in series. I think they also use resistors that aren't likely to short or go low.
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7th Dec 2019, 10:33 am | #43 | |
Heptode
Join Date: Feb 2007
Location: West London, UK.
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Re: Neon Tester Screwdrivers
Vintage Engr mentioned
Quote:
John |
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7th Dec 2019, 3:15 pm | #44 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
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Re: Neon Tester Screwdrivers
Back in the late 1950’s I had a neon tester that had the screwdriver blade cut short and put the rest into a plastic tube, I think resistors came in the tubes, and it was therefore isolated. Used as a guide to tell if line output transformers were working. Only needed to get it within about 2-3 inches and it glowed without having to touch anything.
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10th Dec 2019, 1:58 pm | #45 | |
Nonode
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Location: Dukinfield, Cheshire, UK.
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Re: Neon Tester Screwdrivers
Quote:
In the TV trade at that time, it was common to wave a neon screwdriver near the line output stage to check if it was doing something. A pretty crude test, but it showed signs of life.
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15th Apr 2020, 10:13 am | #46 |
Tetrode
Join Date: Mar 2020
Location: Sydney, New South Wales, Australia.
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Re: Neon Tester Screwdrivers
When I was a meter reader they gave us a Fluke volt stick that had the flashing LED and a beeper in it. Even in bright sunlight you could hear the beeping if it went off.
The only issue I had was if I read a meter under where there was high tension lines or in mobile phone tower control rooms. These would set the thing off in your pocket so you couldnt tell if the meter box was live or not
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16th Apr 2020, 10:08 pm | #47 |
Dekatron
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Re: Neon Tester Screwdrivers
That's pretty much what an Approved Seaward KD1E HV tester consists of: chain of potted resistors and a neon visible through a window. Except the Seaward tester has to be earthed.
A long time ago I once saw that our DNO (NORWEB back then) used a neon HV tester on V/T circuit spouts that DIDN'T need to be earthed.
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17th Apr 2020, 11:17 am | #48 | |
Nonode
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Re: Neon Tester Screwdrivers
Quote:
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17th Apr 2020, 11:35 am | #49 | ||
Hexode
Join Date: Apr 2017
Location: Buderim, Queensland, Australia.
Posts: 428
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Re: Neon Tester Screwdrivers
Quote:
Very few in the trade use neon screwdrivers. These tradesmen are still alive. They use rated DVMs and Test Sets. If these are not available, work stops. Most employers ban screwdrivers. |
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18th Jun 2020, 6:31 pm | #50 | |
Hexode
Join Date: Jun 2020
Location: Manchester, UK.
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Re: Neon Tester Screwdrivers
Quote:
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19th Jun 2020, 4:37 pm | #51 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
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Re: Neon Tester Screwdrivers
A neon screwdriver will work with DC mains, unlike the more modern "voltstick" type of non contact testers which are strictly AC only.
DC mains are virtually extinct in the UK, but might still exist overseas. I know of at least two UK installations with 250 volt batteries. |
19th Jun 2020, 4:49 pm | #52 |
Guest
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Re: Neon Tester Screwdrivers
(I may have said this before) As a final check I short all the "dead" wires together and then to ground. People have said, "It might go bang". At least I survived to hear it.
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19th Jun 2020, 5:19 pm | #53 | |
Dekatron
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Re: Neon Tester Screwdrivers
Quote:
It is completely fair and reasonable - and a great confidence booster - for the SAP to touch any hitherto live bits in the presence of the Competent Person who is just about to work on it. In fact, the Engineering Technicians about to dive in INSISTED on it!
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Regds, Russell W. B. G4YLI. |
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19th Jun 2020, 7:18 pm | #54 |
Pentode
Join Date: Oct 2017
Location: Newton-le-Willows, Merseyside, UK.
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Re: Neon Tester Screwdrivers
there are still legitimate uses for a neon tester and no other tester will work and that is when testing polarity on a TNCS incomer!
As the neutral and earth only split inside the service head you cannot test between live and neutral and then live and earth to confirm that the live is actually live and not the neutral,in fact there's a tool called a Testoscope for this, basically it is a neon screwdriver but the end hasn't got a screwdriver blade,just a point. I've been in the industry for over 30 years and this is the only time I would use a neon tester. I've seen them light on a cable that was cut at both ends,purely to induced voltage in the cable I've seen them not light when on a known live because the user had rubber soles on his shoes and was standing on a wooden floor, but the worst one was when an apprentice dropped one in a sink full of water,he dried it off and put it back in the toolbox without saying anything. The electrician got a nasty belt shortly after when he used it to test a ceiling rose. That said it is a bit like test prods on meters and such GS 38 states they must have no more than 3mm of bare metal showing, that's dangerous at times, I've seen sparks thinking the item they are working on is dead but it turns out the tip of the prod hasn't made contact with the terminal. I like a good 10mm of metal exposed, if you can't handle a probe safely then in my opinion you have no business working on the stuff. I totally agree with Russel regarding touching stuff as an AP, in my job I quite often have to isolate kit for a strip out and I always, after making sure it is dead, make a point of showing the other workers that it is dead by touching the cables at the terminals, as he said, it gives them confidence in you. Recently I was working on a third rail system on a certain underground railway, now it runs at 750v and there are two types of tester for this, one is known as the CRID, or current rail indicating device, used to be known as a 'box of eggs', this is 2 boxes with handles that are placed one on the track rail and the other on the conductor rail, perfectly safe. The other is a pair of black tubes about 20mm in diameter with a cable between them, in the end of one are 3 leds. Partway down on each tube is a large plastic collar, this stops you slipping a hand down and contacting the live rail, not a good idea. Anyway we're on this job and the electrical supervisor from the rail company comes down toprove the rail dead, he then pulls an ordinary Fluke tester out of his pocket to test with! Now ok the Fluke will handle the voltage no issues, but he has zero protection if his hand slips, what an idiot. |
19th Jun 2020, 7:57 pm | #55 |
Dekatron
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Re: Neon Tester Screwdrivers
Would this be a box with lamps connected in series, like a giant test-lamp? I remember as a kid watching 'Blue Peter' and Noaksey went down the underground with the night maintenance team, and I saw them using one of those!
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19th Jun 2020, 8:09 pm | #56 | |
Pentode
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Re: Neon Tester Screwdrivers
Quote:
some rail testers,the first is a very early 'box of eggs' the second a modern self testing version and the third a modern test lamp set for the same thing,note the hand guards Last edited by philthespark; 19th Jun 2020 at 8:19 pm. |
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20th Jun 2020, 1:09 am | #57 |
Dekatron
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Re: Neon Tester Screwdrivers
I once watched a film about overground live rail trains.
After the power was switched off they put a shorting link across the live and running rails before walking all the passengers from a broken down train to a near by location where a replacement bus was waiting for them. |
20th Jun 2020, 2:37 pm | #58 |
Dekatron
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Re: Neon Tester Screwdrivers
More crowbar than screwdriver I'd have thought.
This and previous threads have probably summed up all there is to know on the subject. Useful, as long as you understand its limitations. |