*random* Who's bright idea was it to make PSU heatsinks electrically 'hot'?

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Petra

Gawd
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Jul 8, 2003
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Okay, now, who's bright idea was it to make PSU heatsinks electrically 'hot' as well as thermally hot? WTF were they thinking?!!?! I mean, here I was just making a few modifications/repairs to my Antec True430 PSU and I decided to test it real quick by jumping the PSU with a paperclip before I put the housing back on it (so that I wouldn't have to take everything apart again if something was wrong). Anyway, in the process of doing that, my finger somehow managed to touch the larger of the two heatsinks within the PSU...and that's when the lights dimmed, literally.

The good news is that the PSU appears to be working fine and I seem to be okay :rolleyes: (other than having a small headache, a sore finger, and a slight lingering feeling of "fuzziness" which seems to be fading).

Anyone happen to know why a PSU would be designed to have current running through the heatsink(s)? It seems like a pretty stupid thing to do...then again, what I did probably wasn't very smart either. :rolleyes:
 
hmmm that's wierd, didn't know there was that much electricity in the heatsinks
 
I would honestly go to the hospital man... 100mA can kill a person.. who knows how much went through you.. i mean the lights dimmed?!
 
Well, either the lights actually dimmed or it was just my vision totally crapping out on me... I'm not quite sure which. (hell, a hairdryer will make the lights dim in this house :rolleyes: ) However, I really don't think that this warrants a trip to the hospital... I mean, yeah, I do still feel a little strange and I'm a little more twitchy than usual but I'm pretty sure I'll be fine.

You know.... I'm kinda tempted to take my multimeter to that heatsink and find out how much I really got hit with. :D

...on second thought, maybe that wouldn't be such a good idea. (the experience may have been interesting, however, I don't think that I'm quite ready for round two just yet :rolleyes: )
 
Depending on the design, it may be easier to ground the heatsink the tranisistors are attached to, as opposed to electrically isolating them from the HS and grounding each one individually.
 
I've had some encounters involving a metal grass cutter and an electric fence, and another time a hat with a metal gromet and an electric fence. I'm pretty sure the sun didn't dim, so it probably was your eyes. Did you see some stars? I certanly did in the head meets fence incedent. One of my freinds little sister was unpluging something and tuched one of the prongs at the same time she was leaning ageinst the electricly grounded fridge. I'm a bit fuzzy on the details, but I think she had really big electrical burns on her arm, and that she didn't go to the hospital or any thing. I think you're either dead or fine if you get zapped.

also the electricity has to have some place to go to really get you. My mom had this lamp that I was moving with it still on. I heled it by the metal piece right under the bulb with the switch in it. I was like that doesn't feel right, and carried it the rest of the way by the glass base. Later I tested it with a multi meter 120 volts! No big zap because I was standing on a dry tile floor with only my bodies capacitance for the electricity to flow to.
 
After juicing myself with 240 volts when repairing my dryer, getting hit with weenie power like that only makes me tingle now. Though its not a good idea to open up a power supply and work in one, since those capacitors hold quite a charge and will send you to your maker if your not carefull.
 
Originally posted by RancidWAnnaRIot
I would honestly go to the hospital man... 100mA can kill a person.. who knows how much went through you.. i mean the lights dimmed?!
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Well if he's not dead yet, his heart is still working :p

It's not really that anyone purposly made them hot, but since they are touching various transistors and such, they are prone to being poorly insulated.
 
Originally posted by Vertigo Acid
It's not really that anyone purposly made them hot, but since they are touching various transistors and such, they are prone to being poorly insulated.
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Oh, okay, I suppose that makes sense... I just happen to be one of those types who tends to think that the entire world is out to get me :D

As a side note, this shock wasn't nearly as bad as the one I got while fixing an old 21" CRT monitor... but it still felt really freakin' weird and kinda surprised me because I didn't expect those heatsinks to be hot.
 
Glad you weren't hurt and glad to see Darwism didn't get ya as well. :D

I guess thats why they put those warning labels on them saying stay out of them or risk electrocution.
 
Reminds me of when I was 4 years old, we were on a vacation in Mexico... I had the motel room key, and decided I'd pretend to be driving a car, so I stuck it in the closest ignition-like thing, the big slot in the wall socket. I remember everything went extremely blurry for a few seconds, then I pulled it out and my vision slowly returned to normal... I can't believe I still remember that. Must have fried itself into my memory :p
 
Well for me it was a Compaq LTE screen. The caution sign said "Warning 640V 3A" And I was screwing the brightness board back down and the screw driver hit the two main power wires. All the lights got dim and I had a vibrating feeling all over. The headache only went away when I went to sleep. After that PSU shocks feel like nothing.:D
 
When i was little i used to stick my pinky finger in sockets, yea..the makings of a rocket scientist.

Another time my sister has her clothes dryer on a wet floor, something must have been up cause when i went to touch the handle POOF! ZIP! BOP POW (just wanted to use comic book words) I felt like poop for a few min hehe.
 
Originally posted by StephenIsTheMan
I've had some encounters involving a metal grass cutter and an electric fence, and another time a hat with a metal gromet and an electric fence. I'm pretty sure the sun didn't dim, so it probably was your eyes. Did you see some stars? I certanly did in the head meets fence incedent. One of my freinds little sister was unpluging something and tuched one of the prongs at the same time she was leaning ageinst the electricly grounded fridge. I'm a bit fuzzy on the details, but I think she had really big electrical burns on her arm, and that she didn't go to the hospital or any thing. I think you're either dead or fine if you get zapped.

also the electricity has to have some place to go to really get you. My mom had this lamp that I was moving with it still on. I heled it by the metal piece right under the bulb with the switch in it. I was like that doesn't feel right, and carried it the rest of the way by the glass base. Later I tested it with a multi meter 120 volts! No big zap because I was standing on a dry tile floor with only my bodies capacitance for the electricity to flow to.
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electric fences won't kill you, they are higher voltage so you get quite a shock, but very very low current, so it won't kill you or harm you... volts jolt, mils kill.

as for the threadstarter: that's strange. don't see why current would be flowing through the heatsink at all... just make sure the sink isn't grounded somewhere, that could be dangerous if another component touches it. something's gotta be wrong there, can anyone else verify there heatsink being electrically hot?
 
I've heared many cases of heatsinks being electrically "hot", I don't think it's rare. I have no idea why, but it seems to be pretty common
 
Originally posted by RS3RS
I've heared many cases of heatsinks being electrically "hot", I don't think it's rare. I have no idea why, but it seems to be pretty common
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It's common for heatsinks in PSUs to be used for ground. It probably offers some advantages over just using the ground pin on the MOSFET or similar.

Anyway, the first rule when working with powered electric circuits that have the potential to kill you is to assume that any conductive part of it (including heatsinks) has current running through it.

The second rule is to use only one hand when you do have to touch something.
 
Uh, isn't aluminum an insulator?

When I was younger, I grabbed an electric fence, not knowing what it was. I can remember my entire body went completely tense for an instant. Then, I waited a moment, and pondered... Then I did it again. :p

Oh... I was fooling around in the Computer Tech Room at my HS. We had a dead hard drive and an AT power supply. And some screwdrivers, my knife, and some other random shit. :p Well, we plugged that hard drive in and turned the PSU on. we were running screw drivers and my knife over random leads. I wanted to get a better angle on one of the chips, so picked it up. In a moment, everyone was poking it with various things, and I can remember feeling the STRANGEST thing in my life.

I was holding this sucker in my left hand, and suddenly all of the muscles in my left arm started to tighten up. The my right hand spazzed. Then I dropped that bastard hard drive... My heart was all funky feeling, and my left hand was numb... Also, everything was in slo-mo for about 20 minutes. Someone would say hi to me, and I'd sit there and stare into nothing for 2 minutes then look up and say 'hi.'

Someone else who had been in the other room told me afterwords that the lights dimmed...

Oh, also, on this topic... We took a single AT PSU, and something like 150 cheap ass PI heatsinks with fans, and connected them all to it. Then we turned it on... :p It was quiet, but it still sucked. :p
 
I realy hope he is...

if you touched the hs while trying to jump the pins, you could verywell make yourself the line for the ground.

getting shocked is fun... like discharging capasitors in disposable cameras (owch) or having to plug and unplug a light b/c the switch is dead and your finger between the face plate and prong making you the path of last resistance, or cutting a coard only to find out your friend didnt unplug it like sai he would
 
Electrically hot heat sinks are very common especially in TV sets, I see it all the time.
 
Originally posted by RS3RS
Reminds me of when I was 4 years old, we were on a vacation in Mexico... I had the motel room key, and decided I'd pretend to be driving a car, so I stuck it in the closest ignition-like thing, the big slot in the wall socket. I remember everything went extremely blurry for a few seconds, then I pulled it out and my vision slowly returned to normal... I can't believe I still remember that. Must have fried itself into my memory :p
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i did the same thing when i was a kid, good thing i wasn't grounded o_O
 
Originally posted by ’m‚³‚ñ
I was holding this sucker in my left hand, and suddenly all of the muscles in my left arm started to tighten up. The my right hand spazzed. Then I dropped that bastard hard drive... My heart was all funky feeling, and my left hand was numb... Also, everything was in slo-mo for about 20 minutes. Someone would say hi to me, and I'd sit there and stare into nothing for 2 minutes then look up and say 'hi.'

Someone else who had been in the other room told me afterwords that the lights dimmed...
Click to expand...

Yeah, that's kinda what this felt like... Except it was my finger that was doing the spazing and I had this incredibly strong warm, vibrating-like feeling that went up my arm, through my chest, and then everywhere. Somehow the PSU ended up on the floor and I ended up in my chair (which was right behind me) staring at the PSU. I felt really strange for a couple of hours...

I would like to know how much voltage/amperage was going through that sink, though... heh :D
 
The reason the heatsinks are hot is because if you have to insulate the sink from the devices you lose some of the heat transfer. Think of putting a non conductive layer of rubber or something between your CPU and your heatsink on it. Just doesn't work all that well.

If you are going to screw with any power device just remember the one hand rule. Only use 1 hand to touch the thing and keep the other in your pocket and not touching anything that could possible be a ground. It's a shorter distance figertip to fingertip than finterip to toe so you know what the easiest path for the current to flow is. That and your heart typically sits between your two shoulders which leads to some problems as well.
 
I measured the voltage on mine and came up with around 65V AC. This was off an old supply that still gives out correct voltages but has that burnt smell so I don't use it. I suppose I could measure the current but I really don't feel like shorting it to the ground in the wall with my multimeter. I could probably get you a number but it's not really worth it.
 
Originally posted by Anarchist4000
I suppose I could measure the current but I really don't feel like shorting it to the ground in the wall with my multimeter. I could probably get you a number but it's not really worth it.
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Of course not. To get the right reading, short it to ground through yourself. Much better.

:D
 
Originally posted by Anarchist4000
If you are going to screw with any power device just remember the one hand rule. Only use 1 hand to touch the thing and keep the other in your pocket and not touching anything that could possible be a ground. It's a shorter distance figertip to fingertip than finterip to toe so you know what the easiest path for the current to flow is. That and your heart typically sits between your two shoulders which leads to some problems as well.
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Truly a rule to live by ;)
 
Originally posted by Anarchist4000
I measured the voltage on mine and came up with around 65V AC. This was off an old supply that still gives out correct voltages but has that burnt smell so I don't use it. I suppose I could measure the current but I really don't feel like shorting it to the ground in the wall with my multimeter. I could probably get you a number but it's not really worth it.
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65vAC, eh? Hmm.... I wonder how many amps... ;)

Oh, BTW, here are some crappy pics of the finished PSU (Just thought you guys might be interested):

DSC00288.JPG

The painted PSU housing (cobalt blue metallic)

DSC00287.JPG

A closer look

DSC00290.JPG

The finished PSU, complete with neon blue (UV reactive) FLEXO sleeving and blue heatshrink.

DSC00289.JPG

Another closer look.
 
I've been hit with: electric fence around a horse stable, the ol' "forgot to unplug the lamp while sticking finger in it", zapped by grounding myself while touching spark plug wires, and the best was while taking apart a camera - touched a capacitor and got the shock of my life.;)

btw: nice job:D
 
Originally posted by Petra
Okay, now, who's bright idea was it to make PSU heatsinks electrically 'hot' as well as thermally hot? WTF were they thinking?!!?! I mean, here I was just making a few modifications/repairs to my Antec True430 PSU and I decided to test it real quick by jumping the PSU with a paperclip before I put the housing back on it (so that I wouldn't have to take everything apart again if something was wrong). Anyway, in the process of doing that, my finger somehow managed to touch the larger of the two heatsinks within the PSU...and that's when the lights dimmed, literally.

The good news is that the PSU appears to be working fine and I seem to be okay :rolleyes: (other than having a small headache, a sore finger, and a slight lingering feeling of "fuzziness" which seems to be fading).

Anyone happen to know why a PSU would be designed to have current running through the heatsink(s)? It seems like a pretty stupid thing to do...then again, what I did probably wasn't very smart either. :rolleyes:
Click to expand...

This is not really surprising. They carry a lot of charge, this charge then carries to any metal object, and any good PSU will carry a warning about this, let alone any electronics magazine. Not really smart to do that. :rolleyes:
 
Originally posted by StephenIsTheMan
I've had some encounters involving a metal grass cutter and an electric fence, and another time a hat with a metal gromet and an electric fence. I'm pretty sure the sun didn't dim, so it probably was your eyes. Did you see some stars?
Click to expand...

worst comparison ever. the sun doesn't run on electricity.
 
with electric current it isnt always a case of 'dead' or 'alive'. if you current passed through your body at the wrong part of your heart cycle it can give you an irregular heart beat (which is what they check for at the hospital). if you feel 'funny' and its hours/days later then you should get it checked out.
 
CadniuM: Well, I did feel pretty freaking strange for a few hours but I seem to be fine now...

Monkey34: Thanks. Consider those pics a preview of the finished computer... :D (the whole inside of the case is painted the same cobalt blue metallic with a few silver highlights)
 
Originally posted by CadniuM
with electric current it isnt always a case of 'dead' or 'alive'. if you current passed through your body at the wrong part of your heart cycle it can give you an irregular heart beat (which is what they check for at the hospital). if you feel 'funny' and its hours/days later then you should get it checked out.
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Arrhythmia. If you've been shocked hard enough that the effects don't go away almost immediatly, it's a VERY good idea to go have yourself checked up. You might think you're fine, but be in pretty bad condition. If you feel "funny", it might be your heart dealing poorly with the unexpected electricity.

Also, electrical burns leave very small traces on the surface, while screwing up the inside of the body in an expanding arc from the point of contact.
 
Originally posted by Elledan
You're joking, right?
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Unfortunatly, no. :p But, I have never ever tested this, nor am I stupid enough to actually think that my idea on aluminum was correct. :p I know better now, though. ;)
 
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