Teen electrocuted while salvaging parts from a computer

By on October 12, 2012, 8:30 AM

Anyone that’s worked with computer hardware knows there are some risks involved. Sharp edges inside a case can leave your hands and fingers looking like you lost a thumb-wrestling match with Edward Scissorhands not to mention the potential to short out or otherwise damage fragile hardware. But for one teenager in Shawnee, Kansas, the stakes were much greater as he lost his life while reportedly stripping a computer down for parts to build another.

Local news station KCTV-5 says the teen unplugged the computer before diving in. It’s unclear how long the system might have been powered off before he started working, however.

The incident happened on August 16 although an autopsy recently revealed electrical burns on his body. The official cause of death was deemed to be electrocution; likely the result of touching a loaded capacitor inside the power supply.

Captain Dan Tennis of the Shawnee Police Department said the unnamed victim was “one of those kids,” the type that’s always tinkering with computers and gadgets. Disassembling a computer is something he’d done multiple times before.

Full details haven’t been released nor do we know why he opened the power supply to begin with. The boy’s father arrived home to find his son dead. As the captain pointed out, power supplies typically have all sorts of warning stickers reminding users about the dangers that lie within.

About the only parts to salvage inside a PSU would be a cooling fan or two – cheap components that certainly aren’t worth risking your life to retrieve and reuse.




User Comments: 98

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ikesmasher said:

RIP dude...

But it should be well known that you DONT mess with power supplies unless you're like a trained professional.

nazartp said:

"Electrical burns"? Seriously? He must have been grounded with the wrist band and touched the capacitor with another for electricity to flow through the heart to kill him. It must be really bad luck to get killed by a capacitor charge.

In any case, very sad to read this. My condolences to kid's family.

1 person liked this | Alexmx said:

I'm no rocket surgeon but, does a power supply really stores all that energy after unplugged?

What I always do after unplugging is press the power button on the computer to drain the remaining electricity

EEatGDL said:

Very sad indeed, as the article said: dismantling a PSU is not worth it. Very strange how the conditions could have been in order to make that possible with just a loaded capacitor.

andrewdoyle88 andrewdoyle88 said:

Bad luck Brian takes apart his first computer... Dies. I shouldn't be joking though poor kid just really bad luck

noel24 said:

Yeah, read numbers on those big one, they can store pretty punch. Its a good idea to push a power button on an unplugged PC and leave it overnight for those charges to dissipate, before raplacing fan or capacitor.

nazartp said:

I'm no rocket surgeon but, does a power supply really stores all that energy after unplugged?

What I always do after unplugging is press the power button on the computer to drain the remaining electricity

Sadly it does. Pressing the button does discharge the capacitors though. I am just REALLY surprised that the kid got killed. In 30+ years tinkering (and I'm an engineer by background) I got zapped more than once. Most typical case you brush something with your hand while touching the chassis with the same hand. Painful, but hardly damaging. To get killed you need to really have a path for electricity to flow through your vital organs, primarily brain and/or heart. That's why I think he had an anti-static bracelet properly grounded.

2 people like this | nazartp said:

Out of sheer curiosity computed the energy stored in a typical capacitor. At 120V and capacitance of 2000 uF (pretty typical for a power supply) the energy stored is about 14.5 joules. Standard automatic biphasic defibrillators deliver first shock at around 150-175 J. So 14.5 is pretty low.

nismo91 said:

What I always do after unplugging is press the power button on the computer to drain the remaining electricity

this. then you'll see the system & cpu fan turns on for a brief second.

PC EliTiST PC EliTiST said:

What the? Indeed, I have only opened PSU just once in my life... It was when I built a new PC, I opened the old one to clean the fan and generally the inside... You know, because it is inaccessible, it gathers a lot of dirt after a few years.

My M/B AND my PSU both have LED-lights to warn me when there's still electricity. After I unplug, it usually takes ~3 secs until the LED-lights go out. I hope this indication is enough... Unless the electricity in capacitors is different and the LED cannot measure it...

wiyosaya said:

I smell a lawsuit coming here. No discharge resistor across the capacitor.

However, I highly doubt that the kid unplugged the computer. Voltages and energies are so low in a PSU _AFTER_ you have unplugged it that to me, it sounds like the kid still had it plugged in; otherwise, I don't see the seriousness of the resulting burns.

IF the kid had a CRT and the kid touched the anode lead of the CRT after unplugging it, I could see this happening because the voltage is extremely high.

For anyone interested, the formula for energy storage in a cap is

E=(1/2)*C*V^2

where C is in farads and V is in volts.

Even in typical caps on the mains line of modern switching supplies, the energy is about 60 J for a 240 V main, and will discharge quite quickly once the PSU is unplugged as it continues to power the switching circuits until it discharges.

As I said, I am willing to bet the kid had failed to unplug the PSU from the mains, and touched the wrong spot.

wiyosaya said:

Out of sheer curiosity computed the energy stored in a typical capacitor. At 120V and capacitance of 2000 uF (pretty typical for a power supply) the energy stored is about 14.5 joules. Standard automatic biphasic defibrillators deliver first shock at around 150-175 J. So 14.5 is pretty low.

Agreed.

cliffordcooley cliffordcooley, TechSpot Paladin, said:

You are reading words from someone who has been shocked more times than he can could from wall current while touched a direct ground. I've been bitten by automotive coils which charge up thousands of volts just to be able to create a spark for ignition. Talk about an experience try unplugging a coil while the engine is running(did this once because the key was broke and couldn't kill the engine).

This reminds me of the stories you read or hear about people sky diving and parachute failing then living to tell about it. Reminds me of the people in accidents where the vehicle is shredded and live to tell about it. Then you read a story about someone who hits a ditch at 20/25 miles an hour and dies with little damage to the car.

Lets not forget the people struck by lightning that live to tell about it. And then reading this story about a young kid who appears to do everything by the book, dies from a fraction of the current behind a lightening bolt.

Reading such contrasting stories will always leave confusion in heart and mind of those reading and especially the ones living them. Stories such as this one will never be understood, my condolences to this family for their loss.

Gareis Gareis said:

I'm no rocket surgeon but, does a power supply really stores all that energy after unplugged?

What I always do after unplugging is press the power button on the computer to drain the remaining electricity

I've never thought to do that before, thanks for letting me know

( of course, I've only Been working with computers for a few years...)

Staff
Per Hansson Per Hansson, TS Server Guru, said:

I'm no rocket surgeon but, does a power supply really stores all that energy after unplugged?

What I always do after unplugging is press the power button on the computer to drain the remaining electricity

This is good advice but it only applies when the powersupply is working, and chances are high that if you need to disassemble it it's actually not working properly...

Out of sheer curiosity computed the energy stored in a typical capacitor. At 120V and capacitance of 2000 uF (pretty typical for a power supply) the energy stored is about 14.5 joules. Standard automatic biphasic defibrillators deliver first shock at around 150-175 J. So 14.5 is pretty low.

First of all the primary capacitor or capacitors in a computer's switch mode powersupply (PSU) sit after the input rectifier, which converts the incoming AC voltage to DC voltage. In the case of 120VAC input power there is also a voltage doubler stage active which does what the name implies.

Secondly if the PSU is a modern design it will instead have a APFC stage (Active Power Factor Correction) which sets the voltage at the primary capacitors to ca 400v

I smell a lawsuit coming here. No discharge resistor across the capacitor.

Lawsuit?

Have you actually ever opened a cheap Chinese built PSU? (A $20 PSU as the linked news movie talks about)

Most ones lack any and all input filtering, there are no X or Y capacitors, no MOV's and no coils to be seen, just jumper wires on the PCB where the missing components should be.

What makes you think they would hesitate to not install the primaries bleeder resistor?

I have a charger for a camera right here lacking exactly that, made in China of course.

Actually the majority of PSU's power switches do not switch of both Line & Neutral, which is required by law in Europe.

Because many European countries use the Schuko plug which is not polarized, meaning it can be inserted either way (AC power does not care, so we can flip the live and neutral in any equipment).

This has the interesting side effect that when the PSU switch is off there might actually be power present through the entire PSU all the way back to the switch!

All you have to do is provide a path for the Neutral and there will be a circuit formed.

Like if you hold the PSU's chassis while touching the primary sides heatsinks!

TomSEA TomSEA, TechSpot Chancellor, said:

I'm not a PS guru, so had no clue you could even get shocked, much less die from one.

Not that I'd ever tear one apart, I'd have no reason to. But good thing to know and sorry to hear about the kid.

Guest said:

..err, is this possible? I once get electrocuted accidentally bumped with loaded capacitor from one of my lab device that has diameter twice of my finger and all I got is only minor burns on my breast :p

1 person liked this | nazartp said:

I'm no rocket surgeon but, does a power supply really stores all that energy after unplugged?

What I always do after unplugging is press the power button on the computer to drain the remaining electricity

This is good advice but it only applies when the powersupply is working, and chances are high that if you need to disassemble it it's actually not working properly...

Out of sheer curiosity computed the energy stored in a typical capacitor. At 120V and capacitance of 2000 uF (pretty typical for a power supply) the energy stored is about 14.5 joules. Standard automatic biphasic defibrillators deliver first shock at around 150-175 J. So 14.5 is pretty low.

First of all the primary capacitor or capacitors in a computer's switch mode powersupply (PSU) sit after the input rectifier, which converts the incoming AC voltage to DC voltage. In the case of 120VAC input power there is also a voltage doubler stage active which does what the name implies.

Yep, forgot about that. It's still a very strange death. Electric burns and death just from a cap. Baffles me unless he forgot to unplug the computer. Gotta go show the article to my son - should put some fear of electricity into him.

cliffordcooley cliffordcooley, TechSpot Paladin, said:

After I unplug, it usually takes ~3 secs until the LED-lights go out.
I'm sure it takes longer than 3 sec to take a PSU out of the case and remove the screws from the PSU cover.

After I unplug, it usually takes ~3 secs until the LED-lights go out. I hope this indication is enough... Unless the electricity in capacitors is different and the LED cannot measure it...
If there is any voltage on the circuit, the LED's will be illuminated. There is probably internal switches that cut-off the each rail of power from the PC, leaving main power fully energized. How else could you explain the short burst of electricity while pressing the power button mentioned above. I personally have not observed the short burst but understand how its possible.

the power supply will turn-off all of the voltages except the 5-volt standby voltage (+5VSB). +5VSB is active whenever AC power is present. Once the power supply voltages are stable, the power supply will signal that fact to the motherboard with the PWR_OK signal.
Source link

For a PC to maintain standby power, the main power source can not be turned off. Only power rails can be switched off, leaving the PSU fully charged and waiting for a power good signal from the motherboard. This is a system which was needed for allowing the operating system, control of powering down the PC. Once the motherboard gets a signal from the operating system that it is safe to shutdown, the power good signal is removed which tells the PSU to switch off all rails. The motherboard must maintain power though so it can re-initialize the power good signal and turn the PC back on.

cliffordcooley cliffordcooley, TechSpot Paladin, said:

Gotta go show the article to my son - should put some fear of electricity into him.
Respect would be a better word. Fear can lead to other problems.

Guest said:

I've been shocked many times working on various electronics over the years, some are minor and some hurt quite bad. I've had some friends that have had some bad zaps as well. One ended up in the hospital and they said if he had used his other hand to complete the circuit he may not have survived.

Guest said:

Well its not the jauls that count it is that thing the band was formed around called AC/DC is the big killer. Remember computers like direct current not alternating which is more user friendly. This is why you have that in your house. For dc even in smaller amounts can kill you. It stops your hart. AC alternates at 60 herts to match your pulse a little closer. And DC just fibrillates you. This is why the warning. Same thing in a Television old type though that one is much higher. This is why they tell you never ground yourself when inside a power supply. That is the last thing you want to do and yes you could have been zapped many times but it only takes one time grounded to stop your heart. Also this may have not been fatal if he had worked with a partner for the current probably only stop his heart with no fatal damage. He just needed CPR within I don't know about 5 min. That is about the time you are allotted to avoid serious brain damage. Loner is what killed him or his dad getting home late. I guess this is what the scene is like when you try to prove a warning wrong but all you are able to manage is prove it dead right.

lipe123 said:

He must have had a weak hart to start with or some other underlying issue. In the states those caps only charge upt o 200V and its converted to DC.

The discharge from that is enough to give you a good prick but its almost always between two fingers on the same hand! You'd have to try really hard in the first place to get one hand per terminal/track its soldered to.

If he had burn marks on his body there was MUCH more to this story than just stripping a PSU (which you shouldn't do anyways!).

danhodge danhodge said:

I have messed around with my old PSU trying to retrieve a fan, I didn't realize there was so much danger :S

Not doing that again!

shamus087 said:

Well this has been educational! I always take apart the PSU when I clean the computer, only one time have I heard that those capacitors store power even when switched off and disconnected from the wall, glad I took those words to heart when my buddy told me >.>....

The PSU I noticed attracts allot of dirt, and then when the fan fails and you have to custom mod it to fit the new 120mm fan.

This is crazy, didn't really realize I was playing with fire like I was. Definitely going to take allot more care when I clean it again...

Like other users mentioned though, I always discharge the power before I take it apart, I switch the unit off then disconnect it from the wall then press the power button to make sure none is left over.

Guest said:

Boys and girls, is this really can happen? I mean zapped from capacitor could lead to death? from my experience I once accidentally bumped with the capacitor with the size of a gluestick (but shorter in height) when checking/stripping one of my lab device (of course it's unplugged), I bumped it when I want to reach the cover, then what I got is a small electrical burn on left side of my boobs

treetops treetops said:

Lol its not bad luck the kid was messing around in a power supply unit, which clearly warns people do not f with it, all over it. They really just needs one big sticker saying EVEN WITH POWER CORD UNPLUGGED FATAL CHARGES REMAIN. I wonder if he knew the risk.

My first computer repair college related class in chapter one was like do not ever take apart a psu or monitor unless your a trained professional, your risking deathly electrocution.

spydercanopus spydercanopus said:

Probably a high-powered VIDEA GAME chip. Yall happy now?! Gamin' KILLS!

Benny26 Benny26, TechSpot Paladin, said:

This is going to put the creeps into the next time I open up my PSU for cleaning. Even though I've done it probably more than a 100 times without a single shock I'll still have this on my mind for next time.

There was more to this story I feel.

wiyosaya said:

First of all the primary capacitor or capacitors in a computer's switch mode powersupply (PSU) sit after the input rectifier, which converts the incoming AC voltage to DC voltage. In the case of 120VAC input power there is also a voltage doubler stage active which does what the name implies.

Secondly if the PSU is a modern design it will instead have a APFC stage (Active Power Factor Correction) which sets the voltage at the primary capacitors to ca 400v

Have you actually ever opened a cheap Chinese built PSU? (A $20 PSU as the linked news movie talks about)

Most ones lack any and all input filtering, there are no X or Y capacitors, no MOV's and no coils to be seen, just jumper wires on the PCB where the missing components should be.

What makes you think they would hesitate to not install the primaries bleeder resistor?

I have a charger for a camera right here lacking exactly that, made in China of course.

Actually the majority of PSU's power switches do not switch of both Line & Neutral, which is required by law in Europe.

Because many European countries use the Schuko plug which is not polarized, meaning it can be inserted either way (AC power does not care, so we can flip the live and neutral in any equipment).

This has the interesting side effect that when the PSU switch is off there might actually be power present through the entire PSU all the way back to the switch!

All you have to do is provide a path for the Neutral and there will be a circuit formed.

Like if you hold the PSU's chassis while touching the primary sides heatsinks!

Doublers have not been needed on well-designed, modern power supplies for years. I'm sure you can check this out by reading the specs on any well-designed modern supply - which will not have an input voltage selection switch. Many modern switchers have an input voltage range of 100V-240V, and you don't need to select the input voltage with a switch. Just get the right line cord and plug it in to the local outlet. For example - [link] For a buck converter, it really does not matter what the input voltage is as long as it is sufficiently high enough over the output voltage to overcome conversion inefficiencies.

So, what you are saying is that the kid had not unplugged the supply?

Guest said:

This is rather scary.

I open my PSU every now and then to clean or to maintain it's fan.

Best thing to do is to turn off power and leave the PSU unplugged for 24 hours before maintenance, especially anything with big capacitors.

Staff
Per Hansson Per Hansson, TS Server Guru, said:

Wiyosaya: Uh yea if you had continued to read my post you might have come to the part where I talk about APFC

I guess I could have made it clearer but with APFC there is no voltage doubler stage, only the APFC stage.

But as for the charge in the capacitor this is actually even worse because it is an even higher voltage, which was my whole point to begin with

cliffordcooley cliffordcooley, TechSpot Paladin, said:

Remember the 35mm camera's with flash? Them little bad boys put out a jolt as well.

It never occurred to me how much voltage was needed to operate a camera flash, until I discharged the capacitors in one with my fingers. Talk about a wake up call, that was worse than being shocked by a wall outlet. I instantly formed a question of how a 3V DC device could shock worse than 120V AC wall outlet.

How Camera Flashes Work

The flash trigger is wired to the shutter mechanism. When you take a picture, the trigger closes briefly, connecting the capacitor to a second transformer. This transformer boosts the 200-volt current from the capacitor up to between 1,000 and 4,000 volts, and passes the high-voltage current onto the metal plate next to the flash tube. The momentary high voltage on the metal plate provides the necessary energy to ionize the xenon gas, making the gas conductive. The flash lights up in synch with the shutter opening.

200V :eek: 1000 - 4000 :eek::eek::eek:

From a 3V camera??? WOW

2 people like this | Guest said:

This REEKS of Urban Myth to me.

Guest said:

PSUs should be replaced not repaired. They are so cheap these days, even excellent quality high wattage units are reasonably priced for the job they do. The closest I ever get to the inside of a PSU is with compressed air to blow dust particles out.

Over recent years of fixing computers I have also had instances of a computer running normally at a client's house only to have the PSU "blow" back at the workshop due to excess dust arcing and blowing the PSU as soon as the power cord was attached. Since then I have dusted PSUs out with compressed air before attaching a power cord. Respect electricity.

Guest said:

Well, maybe it is just sensationalism or maybe just bad luck?, I work as IT fixing computers and printers and in my 7+ years in the business I've been shocked by flybacks (CRT Monitors), I have shortcircuited capacitors of around 200V (the big ones), and maybe the worst was the flyback, it left me with headaches for 3 days, but didn't kill me, if this is true, the guy was either bare feet and/or wet and/or suffered of heart affections, only accurate info would tell us.

andymac26 said:

Or just short the cap out with an insulated screwdriver, been doing it for years in my industry. never damages anything.

Yeah, read numbers on those big one, they can store pretty punch. Its a good idea to push a power button on an unplugged PC and leave it overnight for those charges to dissipate, before raplacing fan or capacitor.

9Nails, TechSpot Paladin, said:

My heart goes out to the father. I couldn't imagine the pain and loss of a child. The young man who lost his life working on a hobby that I've done thousands of times myself for business and personal use and never considered to be this dangerous. I hope that this is one of those very unusual set of circumstances and peculiar accidents which aren't common. But to lose a son, a young man starting his life, it is such a heart breaker.

Guest said:

IT always makes me wonder of how ignorant people are! Most users comment that they press the power after having disconnected the power cord. So let me guess you think the capacitor just going to discharge? Let me see. A computer using maybe 5 volts and is run by a 120 volt power source. So you think that small electronics going to just discharge it real quick. A laptop runs 3 to 8 hours on battery. So your system being a little bigger like lets say a desk top computer uses much more power then that. Think again. Even if you press that button for 3 hours there is still a chance that you will have a kick in there. Your best bet is to use gloves. Also when working on power supplies don't ground yourself for that is a deadly mistake. Also think of this a capacitor is an independent circuit. It stores over flow not usage. If there is a circuit it steps down the current by taking the access off. So how do you think you going to discharge it by simply pressing the power button while it is not plug in genius.

1 person liked this | cliffordcooley cliffordcooley, TechSpot Paladin, said:

A computer using maybe 5 volts and is run by a 120 volt power source. So you think that small electronics going to just discharge it real quick. A laptop runs 3 to 8 hours on battery. So your system being a little bigger like lets say a desk top computer uses much more power then that. Think again. Even if you press that button for 3 hours there is still a chance that you will have a kick in there.

Firstly - A normal desktop does not have a battery to keep it running for hours (thats what a power cord is for).

Secondly - They were referring to pressing the Power Button and the motherboard sending a power good signal to the PSU, therefore switching the power rails on and quickly discharging any stored power inside the PSU.

Also think of this a capacitor is an independent circuit. It stores over flow not usage. If there is a circuit it steps down the current by taking the access off.
What???

In short, capacitors are used to level off peak AC voltages to regulate a flat DC output for usage. These capacitors are not a sideline component, they just as important as any other component in the system. One faulty power capacitor and you could have massive amounts of voltage ripple through out the entire electronic system. Notice I said power capacitors because capacitors do have other functions of filtering frequencies.

Your comment disgust me after reading your first sentence. You should never speak of others ignorance, unless you know exactly what you are saying.

Prosercunus said:

I wondering what he was doing. You never try to save or take parts from a PSU. Don't even open them.

Properly dispose of them when they go bad.

Guest said:

A computer using maybe 5 volts and is run by a 120 volt power source. So you think that small electronics going to just discharge it real quick. A laptop runs 3 to 8 hours on battery. So your system being a little bigger like lets say a desk top computer uses much more power then that. Think again. Even if you press that button for 3 hours there is still a chance that you will have a kick in there.

Firstly - A normal desktop does not have a battery to keep it running for hours (thats what a power cord is for).

Secondly - They were referring to pressing the Power Button and the motherboard sending a power good signal to the PSU, therefore switching the power rails on and quickly discharging any stored power inside the PSU.

Also think of this a capacitor is an independent circuit. It stores over flow not usage. If there is a circuit it steps down the current by taking the access off.

What???

In short, capacitors are used to level off peak AC voltages to regulate a flat DC output for usage. These capacitors are not a sideline component, they just as important as any other component in the system. One faulty power capacitor and you could have massive amounts of voltage ripple through out the entire electronic system. Notice I said power capacitors because capacitors do have other functions of filtering frequencies.

Your comment disgust me after reading your first sentence. You should never speak of others ignorance, unless you know exactly what you are saying.

I sugest that you don't comment if you have no clue of what you are talking about. Here is a quote for you.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuitsthat tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes.[

So as you see it is exactly as I commented. You can see a capacitor as an independent of AC or alternating current. It stores direct current while letting AC pass through. So if there is no ac to pass through do you think a stupid thing like a capacitor going to grow brains and convert dc to ac just so in can discharge for you genius.

cliffordcooley cliffordcooley, TechSpot Paladin, said:

It stores direct current while letting AC pass through.
Wrong, the capacitor charges creating a DC voltage which kills AC voltage. There is no pass through AC voltage. The property of having a DC PSU is to convert AC to DC. If you have an AC signal on the output of a DC power supply something is wrong. You should stop now before you embarrass yourself further. Ohhh, thats right you are hiding behind a guest account, no wonder you are saying things that don't make sense.

Just to let you know you are implementing the definition of a filter capacitor as a power capacitor. The difference is one is in series with the circuit while the other is in parallel with the circuit. A power capacitor is placed in parallel with the circuit. A capacitor used as a filter placed in series with the circuit will allow AC frequencies to pass and effectively blocking DC voltages. DO NOT GET THE TWO MIXED UP!!!

So if there is no ac to pass through do you think a stupid thing like a capacitor going to grow brains and convert dc to ac just so in can discharge for you genius.
Lets get one thing straight, by that statement you seem to think that AC is a requirement for discharge. AC voltage can never be stored, therefor never discharged. A discharge will always be the release of a stored DC voltage. AC voltage can jump but that is not the same as discharging.

Do us all a favor and be quiet so we can get back on topic. Paying our respects to the teen that died from a discharge that you obviously don't understand.

Ohh and thanks for the links but I don't need a refresher course in basic electronics.

cliffordcooley cliffordcooley, TechSpot Paladin, said:

So what do you think happens to the rest of voltage or energy when it gets steeped down.
The voltages don't get stepped down, they are switched off, disconnected from the motherboard. Step-down is a term used when voltage goes through a step-down transformer. You can't even get the most basic terminology correct, so why would I listen to you about electronics. Stop talking shit and confusing people. If you didn't spread trash I wouldn't have anything to try and correct. And OMG for the first time in my 40 years of life someone is calling me a bully.

I've derailed this thread long enough, good luck spreading your misconceptions and misguided truths around the Internet. I have had my fill of this conversation and have nothing further to say to you. Its sad really that you would pick this thread of all threads to play your games in.

wartech0 wartech0 said:

I'm not a PS guru, so had no clue you could even get shocked, much less die from one.

Not that I'd ever tear one apart, I'd have no reason to. But good thing to know and sorry to hear about the kid.

PSU are nothing to mess with. The capacitors do carry enough current to kill if you grab a live terminal and ground with both hands. I have had a cap shock me out of a disposable camera before, it hurt pretty bad and luckily I was holding it in one hand. 60mA is enough to kill that isn't really a whole lot either.

Guest said:

That doesn't work. Where does the electricity go if it's not connected to a ground? It stays inside the power supply.

Pressing the power button after it's turned off would only drain any electricity in the motherboard or peripherals back into the PSU. Which is good, unless you plan on opening it...

1 person liked this | veLa veLa said:

It's very simple. Never open a power supply.

Staff
Per Hansson Per Hansson, TS Server Guru, said:

That doesn't work. Where does the electricity go if it's not connected to a ground? It stays inside the power supply.

Pressing the power button after it's turned off would only drain any electricity in the motherboard or peripherals back into the PSU. Which is good, unless you plan on opening it...

No it does not work like that.

When you press the power button on a PSU not connected with a power cord the power stored in the capacitors is discharged and put to use, for example spinning the fans which you can see if you discharge a PSU this way.

However I must stress that this is not a safe way to discharge a PSU, because it assumes the PSU is working properly, which as I said before it most likely is not if you feel the need to open it up and fix it!

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