Hazards of repair

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I especially like the radioactive turntable....

bob

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bob urz
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At one point the article cited says electricity doesn't give any warning. It has always been my experience that I can very lightly touch and move my finger over a hot chassis and feel a sort of vibration. I never got a shock doing that.

Reply to
root

Yes, in fact, not even just a hot chassis, but any equipment that has RFI filters and doesn't have its case grounded.

P.S. The hot chassis thing assumes you don't have your other hand on a ground! It would very likely be more than a vibration in that case. :( :)

P.S.2 This is also the reason you can use a common neon tester to check for live wires without having to connect the other probe to Neutral or Ground.

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 Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ 
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Samuel M. Goldwasser

snipped-for-privacy@repairfaq.org (Samuel M. Goldwasser) wrote in news: snipped-for-privacy@repairfaq.org:

body capacitance couples a small amount of voltage through you to ground. That's how the neon bulb lights.

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Jim Yanik
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Jim Yanik

Fun. Not 100% accurate, though--the getter inside tubes is not mercury, it's usually sodium metal. Mercury has a high vapour pressure, and was used in mercury vapour rectifiers and thyratrons, but not in ordinary tubes. Also there's nothing too nasty about lithium other than that it burns easily.

Happy New Year

Phil Hobbs

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Reply to
Phil Hobbs

Fun. Not 100% accurate, though--the getter inside tubes is not mercury, it's usually barium or sodium metal. Mercury has a high vapour pressure, and was used in mercury vapour rectifiers and thyratrons, but not in ordinary tubes. Also there's nothing too nasty about lithium other than that it burns easily.

Happy New Year

Phil Hobbs

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Dr Philip C D Hobbs
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Reply to
Phil Hobbs

The UK has 240V mains, though. I wouldn't want to use the fingertip test for that.

Cheers

Phil Hobbs

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Phil Hobbs

Nice article on the hazardous of the repair biz but serious overkill. It reads like the warning label on most drugs, which detail every single last possible thing that might go wrong in litigious detail. For example, I have several Geiger and scintillation counters. A few years ago, I was actively looking for hot tubes and materials in antique shops and junk piles. I hardly found anything.

However, like all warnings of the improbable, it only takes one near disaster to justify the warning. In the early 1960's, I was a regular customer of JJ Glass Surplus in Smog Angeles. (My fathers factory was nearby). I thought the major hazard there was having a 10 meter high pile of dead WWII radios fall on me, but soon found something else to worry about. I purchased several IFF transponders for conversion to ham frequencies. I forgot the exact model number but it looked something like this:

I soon discovered that the explosive detonators were still attached to one of the units. I made the mistake of telling my parents, who called the police, which evacuated the neighborhood, and eventually disarmed the radio.

Somewhat later, I worked in the 2-way radio install and repair business in Smog Angeles. The average was one or two work related fatality per year. It was usually from falling off a tower or getting electrocuted by the high voltage found in all tube type transmitters. In general, it made all of us safety conscious for perhaps a few days.

At another low point in my checkered career, I was doing warranty service on consumer audio. Each warranty or test failure would arrive from the distributor with a tag indicating why it had failed. One tag had an ominous warning about a shorted power cord and hot chassis. I applied all the necessary precautions, but all I could find was some distortion in one of the channels. The next unit had a tag indicating distorted audio. However, when I plugged it in, there were sparks and smoke from the unit. Some idiot had switched the tags. I soon built my first test box with circuit breakers.

These days, I fix computers, printers, and whatever drifts into the shop. Not much in the way of hazards found in this stuff. Well, sharp edges on some sheet metal have given me some nasty cuts, and few volcanic capacitors, but nothing really dangerous. Most of the warnings in the article really applies to antique hardware.

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Jeff Liebermann     jeffl@cruzio.com
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Reply to
Jeff Liebermann

More on the radioactive anti-static brush for turntables.

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Jeff Liebermann     jeffl@cruzio.com
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Reply to
Jeff Liebermann

On Jan 1, 9:22=A0am, Jeff Liebermann wrote: > However, like all warnings of the improbable, it only takes one near > disaster to justify the warning. =A0In the early 1960's, I was a regular > customer of JJ Glass Surplus in Smog Angeles. =A0(My fathers factory was > nearby). =A0I thought the major hazard there was having a 10 meter high > pile of dead WWII radios fall on me, but soon found something else to > worry about. =A0I purchased several IFF transponders for conversion to > ham frequencies. =A0I forgot the exact model number but it looked > something like this: > > I soon discovered that the explosive detonators were still attached to > one of the units. =A0I made the mistake of telling my parents, who > called the police, which evacuated the neighborhood, and eventually > disarmed the radio. >

Did you see any of the HD wide shots of the rose parade this morning? The smog issue is way better than when you were here in the '60s.

Happy New Year

G=B2

Reply to
stratus46

It can be subtle. For lecture demo purposes, there's a collection of radioactives in the U. of Washington physics department, including mantles for Coleman lanterns, bright orange "Fiesta" dishes, a navy chronometer (radium dial). Many vacuum tubes have thoriated filaments or cathodes, and that's an alpha emitter so you'll not find the radioactivity until the tube is broken.

That Geiger counter was aimed at a LOT of radioactive material even if it didn't click.

Reply to
whit3rd

I sure did. I wanted to see the Cal Poly Rose Float entry. I missed it on TV, but got it on the internet video feed:

They won the Bob Hope Humor Award - Most Comical and Amusing.

More:

I worked on several floats in the late 1960's and rode inside one year. Good weather, a few clouds, and as usual, moderately cold.

For sure. Cal Poly Pomona (CSU Pomona) is on the "inland empire" side of Kellogg Hill. The ocean breeze from the west blows the smog from Los Angeles over the top of the hill into the Pomona Valley. When the wind changes direction at sundown, the smog piles up against the hill. Do this action a few daze in a row and the smog was actually worse in Pomona than in L.A. It was so bad one summer (in the dorms) that visibility was only about 50ft. My eyes were tearing and breathing was difficult. I visit occasionally and have noticed that the smog situation has greatly improved. Much as I detest having my vehicle smogged, it seems to be working.

Likewise. Happy New Tax Year.... may all your deductions be accepted by the IRS. My new years resolution is to not repeat any of the screwups of last year, and to invent new ones for this year.

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Jeff Liebermann     jeffl@cruzio.com
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Jeff Liebermann

For hunting radioactive antiques, I used a home made scintillation counter. I intentionally made it *NOT* look like the traditional gun for obvious reasons. It's about 10 times as sensitive as my Geiger counter and is perfect for sweeping large areas. In about 1986, I found a bottle of Radithor, which is Radium Water. I later sold it to a collector.

Since about 1995 Coleman lantern mantles use Yttrium Oxide and have no radioactive material. I have some of the really old mantles that use Thorium, an Alpha particle belcher. The old mantles are fairly hot in the plastic bag which blocks most Alpha particles. However, when removed from the bag, the mantles send my counter into hysterics at about 8,000 counts per minute.

My idea of fun was in 1989, when Chernobyl did the meltdown thing, I dragged a 1950's era Civil Defense Geiger counter to the local supermarket and used it to check the produce. The manager was a friend so I wasn't arrested, but I was adequately amused by all the panicky customers and irate staff.

Here's another of my medical adventures with radioactivity and my

1950's era Geiger counter:

My favorite radioactive material is potassium (no sodium) salt. The Potassium 40 is mildly radioactive and will do about 100 counts per minute. Background is about 10 cpm. Sea salt will do about 50 counts. This is always fun to demonstrate in a health food store.

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Reply to
Jeff Liebermann

A fun post to read. Happy New Year

Reply to
JeffM

Not if you're the person involved. The whole neighborhood was very angry with me for having to evacuate for most of the day. Nothing like standing around in bath robe or pajamas for most of the day waiting for the bomb squad to declare it safe to go home.

Also, the shorted power cord scared me quite nicely. Not fun.

Yeah right. New laws, new taxes, same old headaches.

Long ago, one of my roommates received "Family Safety and Health" magazine.

Reply to
Jeff Liebermann

Jeff Liebermann wrote in message news: snipped-for-privacy@4ax.com...

Are you related to this guy? The Radioactive Boy Scout: The True Story of a Boy Who Built a Nuclear Reactor in His Shed " David Hahn, a boy scout, wanted to earn his science merit badge. He could have done an experiment with bicarbonate of soda, like most other kids. But he didn't. He built a nuclear reactor in his shed instead.David Hahn's gospel was The Golden Book of Chemistry Experiments. While his friends were learning to play baseball or dreaming of owning their first car, David was in the middle of an increasingly hazardous trail of chemical experiments. Moving on from routine explosions that forced his work from his bedroom to the garden shed, David quickly determined to build a nuclear reactor. For this he had to make a neutron gun, dupe officials at the Nuclear Regulatory Commission to provide him with information and imitate a professor of nuclear physics in order to obtain purified radioactive elements, all of which he did.David, sporting a gas mask for protection, took to the potting shed with his ever more unstable and dangerous load. His diligence and ultimate success triggered the Federal Radiological Emergency Response Plan: a team of men in moon suits who deconstructed the shed and loaded it and all its contents into steel drums emblazoned with radioactive warning signs. This is a true story. Through it, man's innocent obsession and fatal engagement with nuclear reactivity is told with surreal wonder. "

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Reply to
N_Cook

Lithium compounds were used as antipsychotic drugs, but apparently they're pretty nasty stuff and have been replaced with other things.

Reply to
ian field

In article , Phil Hobbs writes

There's some fantastic photos of those on the web. I don't care how safe they are; I'd be very reluctant to go near one, operating or not.

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Reply to
Mike Tomlinson

No relationship or connection. There are some small similarities between his original motivation and mine. I won't go there.

I've read the book with much fascination. Great story and well worth reading. The problem is the book contains a few errors and some omissions possibly intended to prevent imitation. Near the end, he had successfully built a crude breeder reactor. Fortunately it never hit critical mass.

A photo shows the effects of what I guess is excessive radioactive Thorium byproducts (i.e. Thoron gas) exposure:

Also note the photo of his original reactor.

I haven't tried to build a fusion reactor, yet:

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Jeff Liebermann     jeffl@cruzio.com
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Jeff Liebermann

Jeff Liebermann wrote:

Exactly.

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*-definition-of-comedy-is-tragedy-plus-time

Mostly bureaucrats looking like they're doing SOMETHING.

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Changes do keep the lawyers and other criminals occupied figuring out how to end-run the new regulations, showing us all how they're smarter than everybody else.

Reply to
JeffM

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