Teen electrocuted while working on unplugged computer

[sygnus21]

reading through the comments this one was the only decent comment, poor kids family will be devastated.

The lack of respect here for the death of a young person is saddening. He was a geek like the rest of us and his death was accidental. He could've grown to be the next Steve Jobs and his family is likely crushed. RIP. Posted by kurokitsune

His death is tragic, yes, but he was not a geek. A real geek would have known better. A real geek would know how to discharge all remaining power before working on a PSU. Just like people who clean windows on skyscrapers know they should be wearing a safety harness at all times.

Apparently in the tech field, too often you see people who think they know it all, and sadly this is one of the more extreme results.

I have to somewhat disagree as all of us DON'T necessarily use safe practices while working around electronics. We should, but most of us just take for granted it won't happen since I've done this a thousand times. And when stories like this pop up we realize how lucky we were, and hopefully get back to the basics of safety.

That said, as a youngster I got a good jolt messing with the high voltage fly back wire on a picture tube. Taught me a good lesson about that wire! Thank god I'm still here. Recently while performing some repairs on my 40 inch CRT tubed TV, I made darn sure I discharged that cap.

I also have to admit I’ve opened up a few power supplies and poked around myself

Anyway, it's good that Brink posted this as a reminder that we can't take electricity for granted... even in a computer. Hopefully some learn from this tragedy.

 

[strollin]

All it takes is 28Vdc and 50milliamps to stop your heart. Be careful people.

It only takes a small amount of current to pass thru your heart and interrupt the rhythm of your heartbeat. How much voltage is required to do that varies greatly due to many factors such as how close to the heart the contact point is, the moisture content of your skin, humidity, etc...

 

[gregrocker]

Does holding the power button for x seconds actually discharge the residual power in the capacitors or is that for something else?

Yesterday my nephew was swapping in a new PSU for my Dad's desktop which was left only with a blinking green LED on back of PSU. He reported that when he plugged up the new PSU it had a solid green. Does this LED show residual power, or just power on?

 

[Carl Lawrence]

I really do feel sorry for those parents. Whatever he thought he was doing, he obviously didn't heed any warnings etc at all.

 

[brianzion]

so sad 16 years is nothing thanks for sharing this brink

 

[brianzion]

Does holding the power button for x seconds actually discharge the residual power in the capacitors or is that for something else?

Yesterday my nephew was swapping in a new PSU for my Dad's desktop which was left only with a blinking green LED on back of PSU. He reported that when he plugged up the new PSU it had a solid green. Does this LED show residual power, or just power on?

even when you think you have discharged the psu by pressing the power button down the capacitors still hold power same as a old style tv etc, i used to work on coolers many years ago and when we unplugged them to refurbish them we had to discharge the capacitor connected to the refrigeration unit using a heavy insulated tool that shortened it out.

 

[gregrocker]

This thread may literally be a lifesaver because I was soon going to take apart my Uncle's big screen plasma TV to see if I can spot capacitor damage after it (possibly) fried during power surge. I have a video showing how to do this but with nothing said about discharging residual current. Will a voltage tester suffice held on the leads of a capacitor which appears to need replacement?

 

[Dwarf]

Discharging a capacitor involves placing a load across its terminals so that the stored energy is dissipated safely. The load is typically a wirewound power resistor, although a mains light bulb can also be used. If a voltmeter is connected in parallel, you can also see the residual voltage reduce until it is close to zero (although it will probably never actually be exactly zero).

A word of warning: Never touch the terminals of the capacitor directly, and also be aware that any residual power left in any other capacitors could potentially recharge the capacitor you have discharged. Ideally, you need to isolate one of the capacitor terminals from the rest of the circuitry to prevent this from happening. Above all, never try to discharge a capacitor by merely shorting its terminals, as this can lead to the capacitor rapidly overheating, with the resultant possibility of it exploding or even catching fire (or both).

 

[sygnus21]

Does holding the power button for x seconds actually discharge the residual power in the capacitors or is that for something else?

Yesterday my nephew was swapping in a new PSU for my Dad's desktop which was left only with a blinking green LED on back of PSU. He reported that when he plugged up the new PSU it had a solid green. Does this LED show residual power, or just power on?

Yes. And some capacitors can hold charges for days, maybe even weeks! Also some can hold large amounts of current. But, I would think a typical power supply's capacitor would only hard a charge for a couple of hours.

- HowStuffWorks "How Capacitors Work"
- How to Discharge a Capacitor: 5 steps - wikiHow

 

[brianzion]

This thread may literally be a lifesaver because I was soon going to take apart my Uncle's big screen plasma TV to see if I can spot capacitor damage after it (possibly) fried during power surge. I have a video showing how to do this but with nothing said about discharging residual current. Will a voltage tester suffice held on the leads of a capacitor which appears to need replacement?

thanks dwarf has answered with good advice for you gregrocker exactly what i would of told you for discharging a capacitor.

 

[gregrocker]

Thanks. Is it true that a blown capaitor in a Plasma TV may appear as such, like bulging capitors in mobos? Is it then worth replacing the capacitor on a 5 year old Plasma TV providing adequate and tested discharge is done of the entire power supply?

The TV is already replaced so it's only a tech project..

 

[sygnus21]

This thread may literally be a lifesaver because I was soon going to take apart my Uncle's big screen plasma TV to see if I can spot capacitor damage after it (possibly) fried during power surge. I have a video showing how to do this but with nothing said about discharging residual current. Will a voltage tester suffice held on the leads of a capacitor which appears to need replacement?

This method gets the job done, and is one I used: How to check for high voltage and discharge - YouTube

Thanks. Is it true that a blown capaitor in a Plasma TV may appear as such, like bulging capitors in mobos? Is it then worth replacing the capacitor on a 5 year old Plasma TV providing adequate and tested discharge is done of the entire power supply?

For the most part yeah. But it depends on difficulty, price, and skill. I've replaced two capacitors in my TV. The capacitors cost about 10 bucks a piece, but the task took about 4 hours due to the difficulty of getting to the part(s).

 

[brianzion]

Discharging a capacitor involves placing a load across its terminals so that the stored energy is dissipated safely. The load is typically a wirewound power resistor, although a mains light bulb can also be used. If a voltmeter is connected in parallel, you can also see the residual voltage reduce until it is close to zero (although it will probably never actually be exactly zero).

A word of warning: Never touch the terminals of the capacitor directly, and also be aware that any residual power left in any other capacitors could potentially recharge the capacitor you have discharged. Ideally, you need to isolate one of the capacitor terminals from the rest of the circuitry to prevent this from happening. Above all, never try to discharge a capacitor by merely shorting its terminals, as this can lead to the capacitor rapidly overheating, with the resultant possibility of it exploding or even catching fire (or both).

good sound advice the tool we used had clips on for the terminals to be connected to a large box with a special device inside to take the charge everything was heavily insulated i cant remember what it was called.

 

[Zepher]

Does holding the power button for x seconds actually discharge the residual power in the capacitors or is that for something else?

Yesterday my nephew was swapping in a new PSU for my Dad's desktop which was left only with a blinking green LED on back of PSU. He reported that when he plugged up the new PSU it had a solid green. Does this LED show residual power, or just power on?

That just shows the status of the psu, no led or blinking led means a fault in the output if the psu.

I've got to change 2 capacitors in my left Alesis M1 Active MK2 speaker. This 2 caps sit right next to a heat sink and dry up faster from the extra heat over time. Took 10 years for this one. I already replaced them on the right speaker about 6 months ago.

 

[NoN]

Does holding the power button for x seconds actually discharge the residual power in the capacitors or is that for something else?

Yesterday my nephew was swapping in a new PSU for my Dad's desktop which was left only with a blinking green LED on back of PSU. He reported that when he plugged up the new PSU it had a solid green. Does this LED show residual power, or just power on?

Poor guy...

That's what i thought when holding power button to discharge statics, but no!!!

I've tested it against my will while cleaning a little my computer.

The green light was off and i was pretty sure nothing could happen, but while vacuuming with low air pressure inside i certainly made a little static and the green led power on for few seconds.

The card is protect by low emi and surge....so that was nothing to damage the components, but I understood i'd better not do that again for the components and for me either.

Now i perfectly know that even all unplug that damn psu holding charge.

 

[mjf]

Discharging a capacitor involves placing a load across its terminals so that the stored energy is dissipated safely. The load is typically a wirewound power resistor, although a mains light bulb can also be used. If a voltmeter is connected in parallel, you can also see the residual voltage reduce until it is close to zero (although it will probably never actually be exactly zero).

Great advice. I'm an EE and anyone can become complacent. I remember as a young eng technicians watching my moves when working in the power supply industry.

Maybe a safety sticky under hardware Brink?

 

[galaxys]

Bummer. Also be careful of moisture or spilled drinks around cords/plugs.

 

[JimJoe]

My first electronic training was on large vacuum tube/valve radars. High voltage and high amperage. I have noticed the safety around power taught us in that situation has never been mentioned in any computer class I have taken.

My condolences to his family and friends.

 

[legacy7955]

A real tragedy....So unfortunate and preventable as well. My condolences to the family of this aspiring "geek".

I think the reason that the possibility of electrocution from a computer is not often thought of is that past the power supply itself (in current computers) the voltages are very low and will not do serious harm. But the power supply of every PC until present can be lethal if not handled carefully. While the line voltage is also deadly the juice from those big caps can and is just as deadly.

I agree with others that unless you are properly trained in AC/high voltage DC electronics NEVER open or carelessly handle the power supply!

Thanks for posting this Brink, I think you brought attention to something that is very overlooked in the PC world.


PLEASE BE CAREFUL !

 

[ICIT2LOL]

Well from my point of view the report was rather callous insomuch that as someone has already said as teens we are invincible and hey we knew it all back then. It certainly didn't show much compassion but hey what is that today when human life is so cheap GGRRRRR!!

Myself would hazard (no pun) a guess that this unlucky kid touched a really fully charged cap or even if it were not fully charged enough to upset his heart rhythm. He may have also had some congenital heart defect too that exacerbated the problem whereby the shock was enough to stop his heart.

In case anyone is interested this is the mechanics behind those defib machines one sees on those TV shows where the "dead" person is given a jolt to restart the heart. When in actual fact hat jolt actually stops the heart in the hope that some regular sinus rhythm will kick in from the hearts own pacemaker and then again hopefully by the cardiac centre within the brain stem. That shock is delivered by no less than some rather large caps which you can hear charging when getting ready to do the procdure.

In this unfortunate incident it did just that by the sounds of things and I feel sincerely for those poor family of that young fellow. Thinking back it could have been me and you wouldn't have my company right now like a few others I guess who frequent this forum .

If nothing else a timely reminder of what we are dealing with sometimes I feel rather blithely.