Safety Isn't Just a Word
ROBERT C COLLINS (W6TNI)
on
September 29, 2003
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Hi fellow Hams, I'm W6TNI, Bob, and I want all of you to hear of an experience of mine...
First, here's a little background on me. I have been a Ham Operator since 1941 and I have probably built and operated just about every type of communications equipment over the years.
Safety has always been on my mind when working on any life threatening equipment. However, after more than 60 years I got careless and almost lost my life while operating my station. -- I made the mistake of reaching over my HV power supply 2200 VDC. I didn't touch the supply, but believe me it reached me and the jolt that I received is almost indescribable. I made it, but after the shock my vision was effected and my bloodpressure shot up, among other problems.
Please read this and even if I recover my sight and other problems, it could be all over with a simple mistake. So guys, think safety and don't for a minute think that it can't happen to you.
God Bless
73 Bob Collins, W6TNI
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Safety Isn't Just a Word
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by VK3DMN on September 29, 2003
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Something similar happened to me when I was working at a country radio and general electronics shop I used to own. The local taxi operator had brought in their elderly all valve 2 way base radio, and I was giving it a general clean and tune when *wham*.
I'd done many before, and had serviced this particular radio in the past but I got shocked.
The high voltage burnt a black entry hole into the tip of my little finger (which I believe I had extended without realising) and then (somewhat) luckily out the tip of my elbow and into the earthed chassis of the radio.
I saw a white flash and felt like a mule had kicked me and ended up half way across the room. For days afterwards I had a variety of symptoms, some of which persisted for weeks, and the doctors say I was very lucky.
I don't work on high voltage valve supplies anymore, but for those that do... please take Robert W6TNI's advice seriously.
I know I do (now anyway!)
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by AA8SH on September 29, 2003
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Robert, good of you to share the experience with everyone else. It's a little difficult to share one's own mistakes in a public forum, but it has to be done to protect the next guy from himself.
In keeping with that, I will mention the time about 12 years ago when a 45 ft. Southern pine was infringing on my 10m beam. It had to go. Unfortunately for me, I put it through the windshield of my Chevy Citation. While the Citation wasn't the best of cars, it certainly deserved better treatment than that!
The moral of the story is, when ham radio forces us to do something unusual, whether it's going inside an amp or picking up the chainsaw, it's time to stop and think! Thanks, Clark
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by K4IA on September 29, 2003
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As a kid, I lifted up my Heath DX-60 (with the bottom cover off). My finger naturally curled under the lip of the chassis and hit the 800 volt plate supply. The juice passed through my finger and hand to the chassis. A lot happened in that millisecond. I heard the power supply whine, smelled the burning flesh and got knocked on my keester. It burned a hole in the end of my finger that hurt for weeks. Obviously, the one-hand-in-pocket rule didn't save me.
Almost as clever as the time I decided to strip a receiving antenna wire with my teeth. It doesn't take a lot of voltage to get your attention that way.
Problem with electricty is, you can't see it or feel it from a distance. No one would put their hand in a fire. Reminds me of the joke. What are a Redneck's last words? "Hey, wanna see somethin' cool? Watch this!"
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by KE4MOB on September 29, 2003
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I guess I'm kinda lucky. I had a Yaesu amp on the desk that I was cleaning out. The desk had a metal band that went all the way around the desktop. I was standing up, leaning against the desk, with my right palm curled around the edge of the desk.
I reached into the amp (it was off) to move a wire with my left hand...a bright flash and then a BUZZZZ. I felt the electricity go up my left arm, across my chest, down my right arm, and into the metal band around the top of the desk. Threw me up against the wall, burned the tip of my index finger on my left hand and left a nice row of blister on my right palm. Finger hurt like $#%@ and my mouth tasted like pennies. I went outside and threw up.
Funny, we had been working on that amp for 3 hours and had taken the time (each time) to discharge all the caps when we opened it up. Except that last time.
I was a newbie at the time--been licensed about a year. My elmer looked at me, asked me "are you ok?" and then hearing me reply "yes" said "Welcome to Ham Radio!"
Safety is on everyone's mind--right up until the accident happens.
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by AG4DG on September 29, 2003
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Also watch out when you put a polarized capacitor (electrolytic OR tantalum) across a 12V voltage source. I once inserted an electrolytic capacitor the wrong way. It crackled and splattered its contents on the breadboard. Fortunately, I managed to turn off the power supply before anything worse happened.
Recently, I soldered a tantalum capacitor the wrong way on a circuit board. When I turned the power on, the capacitor CAUGHT ON FIRE! Fortunately, I was able to turn off the power supply in time to avoid even serious circuit damage. It's a good thing I didn't have any paper around the capacitor.
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by KZ9G on September 29, 2003
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These stories just reiterate my insistence of built-in interlock devices that short out the HV power supplies when the case is removed. Not only that, but the use of grounded shorting sticks to "short to ground" any residual HV energy supposedly missed by bleeder circuits and interlock devices. Then there's the keeping one hand in your back pocket trick to keep current path to ground from crossing your chest and heart to ground. Please remember, it's the CURRENT through your heart muscle that will stop it, not the voltage.
These safety precautions were learned during on-the-job training as a radio-electronics technician working on 3 and 10 KW transmitters for the U.S. Air Force. Hopefully, this life-saving, unassuming and common sense approach will never leave me. If anyone has any questions about a HV grounding sticks or working around HV circuits in general, please drop me a line.
73 de Steve, KZ9G
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by FJGH on September 29, 2003
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There are 3 issues that anyone working near exposed HV should never forget.
1.) Always keep one had in your pocket. And I mean always. If it really takes 2 hands to do something, you need to put a contant ground on a hv point. I have many times touched the live +3300V on my 3-1000z amp with no shock while not touching a ground with the other hand.
2.) If you need to do work around exposed HV parts, use a grounding strap that is connected at all times. Don't just ground the supply to drain the charge in caps for a few seconds. If you forget to remove it, blown fuses are better than a stopped heart.
3.) The negative side of a power supply is just as dangerous as the positive side.
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by OBSERVER11 on September 29, 2003
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yep, this old dog learned a new trick too! There is nothing like working on solidstate transmitters, you get used to just reaching in and tweaking things with little thought of B++ on the plate anymore... that was until one day, a customer brought in his ebay treasure for me to put on freq... yep, it was an old tube rig, and yep, I forgot...
After I picked my butt off the floor and cleaned the RF burn on my fingers, I said to my self...
no more tube transmitters!
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by KG6AMW on September 29, 2003
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Good information here. You can work on towers, power supplies and amps and get it right 99.9% of the time and still get killed. I propose that we talk to the FCC and recommend that a special designation (live wire emblem) be developed that would appear on FCC licenses for those who have merged with the grid and survived.
KG6AMW
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by KE4ZHN on September 29, 2003
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You can NEVER be too safe around B+! Treat all high voltage amps and rigs like a loaded gun! They can kill you just as easily. Respect is the key here, B+ doesnt care what it takes to reach ground, even if it has to be through your body. Unplug the equipment, and discharge those caps. After getting bit from a cap discharge a few years ago, I found new respect for what B+ can do! I was lucky, it didnt hurt me very badly, but it sure got my attention! Another good idea is to let the amp sit for about 15-20 minutes before even popping the cover to let the bleeder resistors discharge the caps completly. Even after letting it sit, DONT forget to discharge the caps anyway! Never rely on bleeders or interlocks alone to safely bleed down high voltage, these things can and do fail, leaving the caps charged up to zap the hell out of you. Hot tubes can burn you very badly too, so its always a good idea to let the amp cool down. Your life is worth much more then trying to hurry up and save time by fixing an amp for that contest, or to make that rare dx! And most important of all, if your not well versed in how an amplifier works, DONT even think about opening the cover! It may be the last thing you ever do!
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by WB2WIK on September 29, 2003
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Sorry to hear about your accident, and thanks for the excellent reminder.
As a kid, I used a long rope to tie one end of a very long wire antenna to a point about midway up a high tension tower in the field near my home. The antenna worked very well and I figured with 100' of rope at the end, and probably 75' separation between my rope leader and the HT tower itself, it should have been safe.
It wasn't. Rain + pollution = conductor, when 80kV is the potential. That was very exciting, and falls into the "not gonna do that again!" category.
Thanks once more!
WB2WIK/6
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by KC7YRN on September 29, 2003
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Good advice.
My paranoid side points out that the hand-in-pocket rule depends on a roomy, clean working environment. Imagine working on a bench in the basement and backing up against the washing machine, which is grounded, or a water pipe.
Is it possible to build a high-voltage GFCI to serve as another layer of safety backing up the interlock, bleeder resistors and good habits?
What kind of voltage are lineman's gloves good for?
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by KC7YRN on September 29, 2003
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>grounded shorting sticks
There are plans for those in QST, last month I believe.
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by W5HTW on September 29, 2003
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Like KZ9G, I have worked on higher power, non-ham transmitters, both in the military and in the broadcasting industry. Safety is something you absolutely LIVE.
I learned that a pair of jumper cables, standard automotive types, are wonderful tools, for you can clip them to ground and on the particular circuit area on which you are working, and perhaps save your life. Of course, in ham gear they are a bit oversized, but even a small wire with a couple of alligator clips can keep your heart going after a shock.
Don't depend upon safeguards. We had a transmitter, running 10 KW, that shut down. We flipped off the primary power to it, and with no time to work on it at the moment, it sat, no power and no antenna, for about four days. We just put another 10KW rig on the freq and antenna and went on about our business.
Then the engineer dedided to take a look at it and see what the trouble was. In our facility, a thick rubber mat was in front of each transmitter, and it was just about impossible to get into the rig without being on that mat. Under the mat was a concrete channel with steel grating, where coax and control cables (but no AC power) ran.
He removed the front panel of the transmitter. Then using the attached grounding rod, he shorted the output of the power supply pi-net circuit. There was no arc. He then shorted the bottom of the RF choke to the RF amplifier. No arc. After all, the interlock system had already secured everything, right? And it had been off for days, no power applied.
He replaced the grounding rod in its clip and reached inside to move something, perhaps a bundle of wires. And it bit him, big time. The 7800 VDC went through his arm, his body, and out his knee, to the rubber mat and to steel grating. He was knocked completely out, and away from the transmitter. From the control room I and another guy saw the flash and a puff of smoke. My coworker headed out to the transmitter room, telling me told me to call the ambulance.
The man lived, with hole in his hand, a sliced-open forearm that didn't even bleed, and a hole in his knee. In three weeks he was back at work. He fully healed, but carried scars. He returned to work on transmitters. He also got a pair of jumper cables, which is where I learned to like that idea.
What happened? The filter choke in that pi-network had opened. The input capacitor was sitting there like a cocked .45 just waiting to be touched. Despite interlocks and grounding, he nearly lost his life.
I've had many close calls myself, all of them painful. They are learning experiences, but the fact is, if one is fatal, it teaches you nothing at all.
Ed
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by KT8K on September 29, 2003
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As a beginning computer tech (and studying for my novice test - 1978) I got to work on computer monitors. From my ham buddies I had learned to discharge the CRT before working on anything, and I followed that religiously. They taught me that bleeder resistor's often burn open, and that CRT tubes could hold a charge for days, so I was always ready with a makeshift shorting stick (alligator clip lead and old-and-disposable long screwdriver with well-insulated handle). One day, though, after carefully discharging the CRT in computer monitor, as I was removing a driver board, I was reminded (suddenly and painfully) that other capacitors hold charges (380 volts in this case) and should ALSO be discharged. This capacitor didn't have the capacity to push a great deal of current, so it may not have been as dangerous as some of the other incidents people have reported here, but it hurt like heck, and reminded me that lightning can reside in any capacitor supporting a sufficiently high voltage.
Be safe, folks! 73 de kt8k - Tim
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by W8OB on September 29, 2003
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Being a member of the move toward the bright light group after having been seriously zapped twice ( neither of which was my fault), I just want to say you guys that are using the ground prong on the electrical outlets to ground things like your rig and antenna's are asking for big trouble. You big he-men who say awww its only 110 VAC are also asking for trouble. Bottom line when working on HV lock it open at the supply if possible and ground it for safety! Lineman gloves come in two styles I have seen, The smaller 10 kv size and the larger bulky 48 kv both require leather outers for safety and need to be checked for holes before each use. The best thing you can do is if you are not experienced working at these voltage levels is get someone who is!
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Safety Isn't Just a Word
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by KB9RHA on September 29, 2003
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I'll share a couple stories.
I was working for a computer business and was working with a retired teacher who was also an electrician for many, many years. We were running a network cable for a customer and needed to get the CAT-5 down a wall. I went into the ceiling and drilled a hole in the top board. There were at least 3 2x4s stacked on top of each other so it took a little while to get through. While I was drilling, the circuit breaker for that portion of the building tripped. My co-worker asked me if I had at least gotten through yet. I told him I wasn't sure and he said he'd go reset the breaker and be right back. He reset the breaker and came back with a metal rod and told me to stick it down the hole and see if I had gotten through. With my right hand holding the steel beams holding up the roof, I pushed the rod down the hole with my left hand. Immediately I felt my body shaking violently and couldn't see straight. I managed to let go after about 5 seconds and gained my composure. I looked at my co-worker and said, "There's no way in hell I'm grabbing that thing again!" He said he didn't blame me and got a pair of gloves and channel locks for me so I could get the rod out. He then handed me a flashlight so I could see down the hole. I found that I had drilled right into some Romex. Conduit isn't required in Wisconsin. Personally, I prefer conduit, but that's for another thread one day. :D
Here's a funny story of what happened to me when I was in 5th grade and didn't really no much about electronics and electricity. We did that experiment for science class where you wrap some wire around a nail and connect the wire to a battery so you can pick up paper clips. Well, call me Tim Allen, but I wanted to make a stronger electromagnet. What did I do? I went home that day and made a big electromagnet. I took a spool of insulated 20 guage, or around 20, and wrapped about 30-50 feet around a 3 foot long metal rod and attached the ends of the wire to an electrical plug. lol I made sure the light switch was off and plugged my contraption into the outlet and went to the light switch which was about 10 feet away. (I wasn't completely stupid.) I turned on the switch and all I heard was a LOUD spark and the room was instantly filled with smoke. I turned the light switch off as soon as heard the spark and went back to the thing I made and looked at the damage. A good portion of the wire had melted and the thing had melted to and burnt some of the carpet. I quickly got rid of the thing and luckily the carpet was brown so I was able to hide that pretty easily. My windows were opened and noone ever noticed a thing. I finally told my mom about it a couple years ago, about 12 or 13 years after I did it. :D I know better than to try stuff like that....now.
73, Chris KB9RHA
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by KG6AMW on September 29, 2003
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I merged with the grid when I was 6. I was standing in front of an old-fashioned fuse box in a closet that had many fuses present. One was missing and being uninitiated, I stuck my finger in the hole. I woke up on the opposite side of closet and the tip of my finger was burned black. What saved me was a wooden floor. You bet high power scares me.
KG6AMW
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by KC7YRN on September 29, 2003
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>I found that I had drilled right into some Romex.
Yeetch.
Too bad I didn't wire your customer's building. I always put in nail plates whether code requires them or not.
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by KB0GU on September 29, 2003
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In 1977 I reached up and pulled the brown power cord with the orange mark on it from my electrical outlet on the work bench/ham radio operating position. I then waited for the bleeder resistor on the home brew amplifier to drain the filter capacitor bank. Hey the bleeder resistor had always worked before and it looked good now no evidence of overheating or failure. Came back to the supply about an hour later and reached in POW! I woke up on the concrete basement floor with my poor dog licking me and whimpering. As I regained my senses I looked and to my astonishment I had pulled the wrong power cord! That is the last time I ever got lax about discharging a high voltage supply with a chicken stick.
Please be careful and follow the basic safety rules.
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by CODEBASHER on September 30, 2003
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In the Army we had a demonstration of a communication station voltage/amperage safety class using 2280v 3phase battery backup system. They used the site to drain the batteries untill it wouldn't hold the site up and then used an 3/4 inch diamiter 48 inch long crowbar "tossed" across the positive and negative leads.... It stuck there after a lot of sparks flew.... the middle turned red.... then white and then it dripped onto the floor as molten steel.....His comment was..."your ashes would have fallen before you realized you were dead!!" This had a definite effect on the class....one we would never forget!
73's de N0KLU, Mike
Rolla, Missouri
NCI-4743
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by N6AJR on September 30, 2003
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In the U S air force in electronic countermeasures repair, I learned my lesson the hard way too. a particular piece of equipment had a Maggy ( magnatron) in it that was both hydraulically and eletronically sweep tuned. (if I told you any more I'd have to shoot you) this dude was in stand by and has 3 annode rings across the top of the maggy.
I had my one hand in the pocket and rested my arm on the edge of the chassis( bad habit) and accidently got across the #1 and 2 anodes to the tune of about 3 KV, than goodness I was in stand by, if it was in transmit I would have been dead.
It picked me up and threw me 12 feet across and I landed flat to the wall ( so they tell me..it knocked me out) I guess I learned the hard way.
That was in 1967, I now have my screwdriver with the long blade and the wire with 2 aligator clips and clip to the chassis and to the blade of the screwdriver. Its crude but it works. and how many times have You grabbed the wrong end of the soldering iron HI hi ....
73 tom N6AJR
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by N8IWK on September 30, 2003
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I become a long standing grid member at the young age of 7.
I remember curiosoty got the best of me one day when I saw a hairpin on the ground near an electrical outlet.
You know the rest.........
Good thing the breaker tripped or I may not be here today writing about it.
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by KA4KOE on September 30, 2003
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Old receivers are dangerous. If one of the bypass caps is leaky, it may put voltage on the chassis. I had my hand on the outside of the radio and reached for the coax connector (knurl is at ground). BITE. 100v across the chest. Was able to let go, but it hurt bad. Yelled the f word. Girlfriend came running. Hands ended up shaking for three days afterward. This happened in the early 80's. The receiver was an R388 on loan from a friend.
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by KA4KOE on September 30, 2003
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This was a joke played on me onetime.....
I was at field day and using a friends 12v transceiver for CW. The sidetone was very low, so I cracked it open and got out the screwdriver to crank it up some. While I was doing this, two of my "friends" were behind me waiting to strike. One dropped a very heavy book from about 4' onto the hard concrete, while the other let off a 35mm camera FLASH at the same time the book reached zero elevation. FLASH BANG!!!
I just about lost sphincter control. Fortunately no change of clothes was necessary.
Took me awhile to get them back, but revenge is a dish that is best served cold.
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by WILLY on September 30, 2003
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About jokes:
Remember when cars had points and condenser?
Charging up one of those old condensers is easy. Pull off a plug wire, put the wire end of the conderser up in it, and ground the condenser case to any metal. Crank the engine over a few times, and the condenser is charged.
Toss it to a friend, and watch what happens.
About safety:
When working on your car, anywhere near the lines that carry 12V, like running 8 or 10 gauge wire for the radio, always remove all rings and watches.
This is not a high voltage situtation, but a high current situtation. Car batteries can deliver a lot of current. Just think about what would happen if it was going through your metal watch band. It would cook the flesh all the way around.
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by KC7YRN on September 30, 2003
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Good advice in other situations too. You don't want your wedding ring wearing a hole in your lineman gloves.
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by AA9YU on September 30, 2003
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Good article. Not just electricity! I just had hand surgery from slicing through my finger and tendons with a chisel making a loop antenna for the broadcast band. Typing this one-handed! I wish I had been more careful. DON'T PULL ANY SHARP INSTRUMENT TOWARD ANY PART OF YOUR BODY.
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by KI4BCL on September 30, 2003
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We were taught in our radio tech school to also remove any jewelry thats on your hands prior to working on energized equipment. Jewelry conducts (really well too) - plus - when you get shocked - what do you usually do - jerk back - really fast... which could tear up your fingers, damage the equipment, etc...
Great topic and article......
All the best...
Ken
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by K9FE on September 30, 2003
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This topic takes me back to sophomore year in H.S. when I was first licensed. I had been working on a 3 tube 4cx250 amp for 20m. The chassis was scavenged, the power supply transformer was Mil Surplus, very hefty. I was adjusting the tank coil using a 6-inch wooden ruler. I had done this quite a few times before and never had a problem . This time however I had the chimneys off the tubes to provide access to the coil. Plate voltage was 2950 and I had plenty of caps, almost 40mfd. I had been driving the amp with about 10 watts trying to get the tank coils trimmed by spreading the turns. I DROPPED the wooden ruler and by instinct I reached to pick it. BIG MISTAKE! The flash, bang, and kick put me across the room (about 12 feet) I just sat there on the floor dazed for a good 30 minutes before I realized what I had done. I had a nice crescent of flesh burned off the heel of my hand and the base knuckle of my thumb. I think the only thing that saved me a little was the use of a magnetic switch/breaker (1 cycle trip) in the power feed to the High Voltage with a 3 amp trip.
It took a good 10 years for the scars to fade. The feeling came back to my hand about 1 month later and the bad taste left a day later. But the memory will last a lifetime. Respect HV, I could have been a SK instead of enjoying the hobby.
please be careful de K9FE Mike
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by W8FAX on October 1, 2003
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We all need to be careful. I saw a feller refueling a running generator with gas during a field day event becuase they didnt want to shut down for a short. New hams that get into boat anchors need to be especially careful. It's very easy to get careless when your experiance is with the common 12 volts that powers most of the rigs and accessories these days. As pointed out above, even those little table AC/DC radios will put you into a box. Also, if ya don't know...ASK somebody.......
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by KC7BDP on October 2, 2003
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I'm seeing all these horror stories about HV burns; and I have my own "funny-shaped" fingertip, a lump on my head that won't go away, and a typical story. Short form: Almost 20 years ago, a Ham talked me into replacing/neutralizing the final tubes in his 830S; I think he was hoping to turn me from the atrocities of 11 Meters. I was "sure" the radio had been off long enough for the caps to bleed off. I found out otherwise while sitting on a steno chair with my legs and feet curled under the chair on the floor. ZZZZAP! Legs responded by extending rather than contracting; I was knocked cold when the rolling chair hit the rug in the middle of the tile floor. My wife of four weeks woke me up on the way to the hospital and it was decided that it was good that I had married a Nurse!
Only one person mentioned what I know to be most important: HV burns, amperage KILLS. Hi amps also burn as well. While cleaning the cable clamps on my car's battery, I was using an el-cheapo wrench to tighten the clamps; wrench slipped, managed to get my wedding ring trapped between the cars fender and the wrench - on the postive terminal.
I don't wear my wedding ring much anymore; it's pretty rough looking with the melted gold band which matches the scar (with a small gold lump embedded) below the second knuckle of my ring finger. And I'm an electrician (now doing telco work), so I really should know better!
Bottom line: Just because it's solid state, don't believe it's safe! Remember that low voltage requires MUCH current to produce high power. And "current kills".
Jimmy
KC7BDP
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by KE0VH on October 2, 2003
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There is a reason that broadcast transmitters have a rod inside with an insulated handle that is connected to the chassis for discharging all components before reaching a hand or head inside to fix things. That rod is called a "Widow Stick". Fixing up some kind of apparatus for working on our amps is a good idea, then touch all those components with the stick and you won't have a widow, at least if you aren't married.
73' KEØVH
www.geocities.com/ke0vh
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Safety Isn't Just a Word
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by WA2JJH on October 3, 2003
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I have to confess that working on a dual-3-500Z AMP, gave me the second worst zapping of my life!
I did follow the one hand in pocket rule for HV.
IMHO The one hand in pocket for HV work saved my life!
I was fixing a so called mint condition AMP I purchased on EBAY.
I turned off the amp, and did not wait the recommended 60 seconds. The HV cover was off.
My hand touched 3000+ HV and chassis.
The shock was not as bad as a laser power supply I got
10 years ago.
However the partial second degree burn on my right index finger and metacarple 1 was not very pleasent.
If I did NOT follow the one hand rule, I could have
been dead from heart arythmia. Good thing the bleeder resistors were working as well. I would say the AMP was off for 5 seconds.
My hand going there was not intentional. I was sloppy. I reached for a part over the AMP. I WAS NOT LOOKING! I HAD THE TV ON!
Bottom line, when working on HV the one hand rule is a must. My real lesson was not to have ANY distractions
while working around HV!
When I got transmitter duty at a Broadcaster I used to work for, we had the two man rule. One commercial FCC licensed engineer worked on the tranmitter. The other FCC commercial engineer simply made sure the engineer working on the transmitter did not make any mistakes! A 20KW VHF TV transmitter mistake, will kill!
I hope W6TNI (ROBERT) makes a full recovery. Robert
thank you for writing this artical! You have a lot of courage. You sir, are blessed.
73 DE MIKE WA2JJH
GOD BLESS AND 73
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RE: Safety Isn't Just a Word
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by KG6JEV on October 4, 2003
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I've been in electronics most of my life and finally got into ham radio a few years ago. I learned tubes in tech school, back in the 80s, but hadn't touched them in years. Shortly after getting my General ticket, I bought an old Yaesu FT-901DM on eBay. After thoroughly checking it out the day it came, I gave it power and proceeded to check all the knobs and functions. After making my list of items to fix, I turned it off and popped the cover off, including the lid to the PA cage. I was just about to reach my fingers into the cage and pull the caps off the tubes, when a little voice told me I better put a voltmeter on the plate cap. Good thing I did - the meter showed over 600 volts. Made me sit down and think. I've had a lot more respect for tubes, RF and HV since then.
73,
Steven
KG6JEV/4
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The More, Maybe the More Cautious...
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by K4III on October 5, 2003
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Well here are my experiences...
Age 7, those Christmas tree lights had a bent female tooth on one of the 5. Unplugged what I thought was the row of lights and ZAP!
Age 15, Light Bulb blew out. Saw the broken filament and decided to shake the lamp and see whether the light bulb would light up again if the filament made contact again. Say Cheese! Oops...
Age 19, Rewired a 1940s lamp with a metal switch and during the re-wiring feedthrough process one of the rubber sides must have stripped and made contact with the metal mast and switch. Ouch...
Age 21, Was working as Broadcast engineer for a few fm radio stations. Had friend helping me 25 feet down from tower on facility roof. Was working on a 100w Transmitter and there were three FM stations located atop the building all located in the same rack. Told friend to unplug the transmitter and plug I labelled and showed him 20 minutes earlier so I could remove the FM antenna bay. (Don't want to turn off the other 1000w and 250w stations) Ouch, ring of Blisters and almost a 25 foot fall! Wrong plug you #$%#&^#&#&#^% was my response.
Age 23, Was replacing the relay in a 440 repeater system and accidentally touched a non-discharged transformer or wire near the relay. Tingled for about an hour.
Two Months ago, while jumping my cars battery, I connected the leads to the running car and accidentally touched the other ends together. Wow, Spark heaven! No human shock though...
Oh yeah, and when I was about 10 I started a fire by changing a few components on a large stereo system I had thinking they would improve reception.
All this time I've wondered whether living in Europe with 220v would have allowed me to write this today...
And half of these occasions I've never mentioned at all before reading this article... (And probably some I didn't post that I've not even remembered)
Still working on electronics, especially on computers! However I will not open a CRT Monitor or TV. Even thinking safety isn't always enough. It's always a good idea to make sure you either work in groups or with someone else around in case you get into trouble...
And bleed your equipement down after unplugging it by turning it on after removing the plug (AND BACKUP SOURCES). I always find even after unplugging some items, some juice can last for awhile and can show up for a few seconds flipping it on again even with the plug out..
My 2 Burns...
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Safety Isn't Just a Word
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by KD2E on October 8, 2003
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While operating your station, you reached over the HV supply??
Wait a minute...
Do you mean at your operating position the supply has no cover??
I must be mis-reading something.
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Safety Isn't Just a Word
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by KE4DRN on October 8, 2003
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Just want to add a few items
If you need help or if it has been a while since you worked on some equipment, ask for help. Even if you know what you are doing it is good to have somebody around if you get hurt.
If you are tired or things are just taking too long,
STOP right there and continue the next day. Easy to make a mistake and get hurt when you are tired.
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Safety Isn't Just a Word
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by KD5NRR on October 9, 2003
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I'm only 22 now, but about 15 years ago, my parents used to bowl a lot. My sister and I would hang out by the arcade games and waste time until everyone was ready to go home. The arcade games that were housed at the bowling alley were older games that had been played many times. So many times in fact, that the paint had worn off in places that are usually "elbow rests." It just so happened that underneath the paint was metal.
Two of these machines were side by side and someone discovered that when you put one hand on one paint worn metal console, and the other hand on the other machine's console, it was quite a weird feeling. I personally tried it more than once, each time getting the strangest sensation i've ever felt. Lots of us tried it and no one got hurt. We never felt any shocks when making initial contact, and never had any problems letting go.
I was a little strange as a kid, because this incident sparked my interest in electrical outlets. We had one of those old power strips that didn't have seperate plugs, but just two long strips of metal inside plastic casing that let you plug in anywhere along the rails of the power strip. I would touch my little pointer finger and my thumb to the two contact while plugging in an appliance and was able to feel the same sensation as at the arcade. Never did hurt me though. Strange stuff, and I guess i'm very lucky.
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RE: Safety Isn't Just a Word
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by W6TNI on October 11, 2003
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REPLY FOR KD2E AT THE TIME I WROTE THIS THINGS WERE A BIT HAZY HOWEVER HERE IS WHAT HAPPENED THE RF DECK WAS ON THE OPERATING DESK THE HV POWER SUPPLY WAS ON A METAL FREE ROLLING CABINENT DIRECTLY NEXT TO THE OPERATING TABLE IN ORDER TO TUNE THE AMP IT WAS NESSARY TO REACH OVER THE EXPOSED HV POWER SUPPLY STUPID I KNOW AND AGAIN I PAID FOR IT HI IT SURE GOT MY ATTENTION I KNEW BETTER BUT LIKE I SAID IN MY ARTICLE ONE MISTAKE CAN BE THE LAST ONE THE ENTRY WAS FROM THE FOREARM TO THREE FINGERS RESTING ON THE METAL CABINENT I LEFT MY FINGERPRINTS THERE PERMANTLY I WOULD SAY ONLY ITS NICE TO STILL BE HERE BEST 73S BOB W6TNI
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RE: Safety Isn't Just a Word
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by WA1RNE on November 19, 2003
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Bob:
Certainly hope you make more progress toward complete recovery. Many of us have made similar mistakes and luckily survived to talk about it. I remember reading QST years ago and would see the small blurbs that read something like SAFETY FIRST! REMEMBER TO PULL THE BIG SWITCH, etc. Unfortunately, these small sidebars would report some poor guy who didn't make it. Glad you did. You never forget stuff like that..for good reason.
I've known about the one hand rule since I was about 14 - even impressed an engineer one day who was helping me work on a DX-60B. He was relieved to see I knew this and let my dad know I was going about it the right way. I'm sure HE was relieved. (I'm not sure if I will let my son poke around a HV cage.) About 10 years ago, 800 vdc found me; my HA-6 transverter was on the fritz (remember that rig?) and it gave me a wake-up call. I brushed my forearm across one of the plate caps probably doing something similar to what you did.
I'm pretty sure I was tired and should have taken a break - which is really my point. Stay awake to stay alive - never work on HV when you are beat or in a hurry...If your frustrated with a technical problem, take a break and come back in an hour or so - or ask for advice.
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