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Dell Laptops Have Shocking New Problem 475

Posted by CmdrTaco
from the jolt-of-reality dept.
dapsychous writes "A friend of one of my coworkers has noticed a problem in Dell notebook computers (also covered in this engadget article about a problem that has been popping up lately in Dell 17" notebook computers). It seems that these computers are putting out between 19 and 139 (65 according to article, 139 according to him) volts of AC power as measured from any chassis screw vs. earth ground. This has led to several problems including fried ram, blown video circuits, and a stout zap on his left hand. According to him, Dell has tried to keep him quiet about the problem and has even gone so far as to have him banned from a few websites, and threatened him with legal action if he tells people about the problem."
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Dell Laptops Have Shocking New Problem

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  • Non-repro? (Score:5, Insightful)

    by gcnaddict (841664) on Wednesday February 07, 2007 @12:24PM (#17921860)
    I'm running an E1705 (manufactured in May of last year) and I'm not seeing this. Maybe his unit just sucks at grounding. (They're called manufacturing defects for a reason, and last I checked, they're covered by warranty and by law.)
    • Re:Non-repro? (Score:5, Insightful)

      by Tongo (644233) on Wednesday February 07, 2007 @12:31PM (#17921982)
      I don't think the story is about the shock. The story is about how Dell tried to shut him up.

      Maybe the guy should be carefull so that he don't sleep with da fishes.
      • Re: (Score:3, Informative)

        by dgatwood (11270)

        Realistically, I can't see why you'd ever have the voltages claimed by this article inside a laptop. Laptop supplies are usually 24-ish volts. Anybody reporting numbers higher than that probably has something else wrong, like an inverter power cable that is being pinched by a hinge or something. Either way, at the current levels we're talking about, it should be pretty harmless, if a little uncomfortable. However, Dell still should fix their supply design for other reasons.

        I was helping someone on one

    • by Anonymous Coward
      On an older Inspiron 8600 laptop. I contacted Dell Warranty Support and my laptop was replaced with a newer E1505 core duo model within a week.

      Normally I would have been happy, but the new system had inferior graphics and disk drive, and was incompatable with the upgraded RAM in the old system. Dell would not reconcile the issues, and just had their tech support deny my claims.
    • by Walt Dismal (534799) on Wednesday February 07, 2007 @12:49PM (#17922270)
      Speaking of non-repro, if you have the laptop in your lap and your feet in the bathtub, you may never have to worry about not getting a date on Saturday night ever again. It only takes one line voltage zap and Mr. Happy will be terminally depressed, as will his two small buddies. So remember, NEVER put a ground strap on your ankles and sit down to use a Dell laptop during a thunderstorm on Friday the 13th. In Texas. While wearing an aluminized Mylar bunnysuit and no underwear. However, this is all too common.
  • I'm on one of those right now. i will be calling Dell ASAP to see if I am affected.

    *sigh*, Is there not a company we can trust anymore?
    • Re: (Score:3, Funny)

      by Abolo (932400)
      Google? They seem nice.
    • Re:Oh shit. (Score:5, Insightful)

      by Rob T Firefly (844560) on Wednesday February 07, 2007 @12:31PM (#17921986) Homepage Journal

      *sigh*, Is there not a company we can trust anymore?
      Has there ever been?
      • Re: (Score:3, Insightful)

        I know it's fashionable here to bash corporate America and all, but not all companies are big bad corps with a will to shaft you out of your hard-earned money. I trust many big companies because they provide quality products and never tried to screw me, and I trust even more small companies, and if you think about it, I'm sure you do too.

        That said though, Dell isn't in my white list, that's for sure. Michael Dell is in for the money, period...
        • Re: (Score:3, Interesting)

          by evilbessie (873633)
          We like bashing corperate America as we in Europe have the EU (bad as they may be) but at least they occasionally have some balls, like basically forcing Steve Jobs to come out against DRM, having an anti-monopoly commission that, you know, is anti-monopolies. And generally tries to do good for consumers and not protect damn big corperations from f***ing us up the a*** (or a** for those who speak American).
    • Re: (Score:2, Informative)

      by FudRucker (866063)
      get a volt meter and check for voltages between a chassi screw and earth ground, it will most likely be DC current...
    • You trust them? (Score:5, Insightful)

      by Kadin2048 (468275) <slashdot.kadin@x[ ].net ['oxy' in gap]> on Wednesday February 07, 2007 @12:35PM (#17922050) Homepage Journal
      i will be calling Dell ASAP to see if I am affected.

      Um, and why would you expect them to give you a straight answer? They'll probably just play dumb and say they've never heard of the problem. (Which will probably be true, at least for the drone you'll be talking to.)

      Get out a voltmeter and test it; that would seem to be the easiest solution, and less likely to lie to your face than some Customer Service rep. Probably faster, too.

      Until a problem like this becomes terribly public -- and by this I mean more public than just being covered on some technology websites -- I suspect Dell will deny it, except in cases where people absolutely insist that they have a problem, and demand a replacement. In those cases, they'll get a replacement machine just to shut them up.

      So I'd just get out the old multimeter, measure the AC voltage from one of the chassis screws to the nearest good ground, and if it's more than a few millivolts, call Dell and tell (not ask) them that you need a replacement unit.
      • Re: (Score:3, Funny)

        by Pollardito (781263)
        maybe they'll start shipping Dell Voltmeters that don't register any current less than 139 volts free with the purchase of any laptop
        • by Gnavpot (708731)

          maybe they'll start shipping Dell Voltmeters that don't register any current less than 139 volts free with the purchase of any laptop
          I have never ever seen or heard of a current of 139 volts so that should not be a problem.
    • I'm on one of those right now. i will be calling Dell ASAP to see if I am affected.

      You need to call Dell to check if that painful feeling in your fingers is for real?

  • by goldspider (445116) <ardrake79NO@SPAMgmail.com> on Wednesday February 07, 2007 @12:28PM (#17921918) Homepage
    ...it doesn't get much more reliable than that!
  • by swschrad (312009) on Wednesday February 07, 2007 @12:29PM (#17921940) Homepage Journal
    if a power supply doesn't do it, pop out the drive and put in a new chassis.

    is Dell that bad at support nowadays? or is it just another "call me Bob" who has no clue who he's working for this month overseas and doesn't care?
  • by physicsboy500 (645835) on Wednesday February 07, 2007 @12:30PM (#17921958)
    Dell's new marketing campaign should be: Dell: our computers are elecrifying!
    • Re: (Score:3, Funny)

      by gbobeck (926553)

      Dell: our computers are elecrifying!
      That is shockingly clever idea for a current marketing campaign.
  • Only in America! (Score:5, Informative)

    by aslate (675607) <planetexpress AT gmail DOT com> on Wednesday February 07, 2007 @12:30PM (#17921962) Homepage
    Okay, not really, but shouldn't happen in the UK. According to the article:

    "The latest word is that VG's own problems were solved by springing for a three-pronged grounded power adapter"

    You can't get a non-earthed plug in the UK, the earth pin is physically required to open the plug socket. This can be a dummy pin, but you're only able to do that if the unit itself is double-insulated.
    • by b0s0z0ku (752509)
      You can't get a non-earthed plug in the UK, the earth pin is physically required to open the plug socket. This can be a dummy pin, but you're only able to do that if the unit itself is double-insulated.

      Aren't there around 3 types of socket in common use? The tank-like giant socket with three rectangular pins. The socket with three round pins (possibly in two different sizes!). Also an "electric razor socket" putting out 115V in a bathroom. I know the first type is the official standard *now*, but I sa

      • Re:Only in America! (Score:4, Informative)

        by Weedlekin (836313) on Wednesday February 07, 2007 @01:59PM (#17923272)
        "Aren't there around 3 types of socket in common use? The tank-like giant socket with three rectangular pins."

        That's the BS 1363, which was standardised as an electrical appliance connector in 1962. It contains an integral fuse which can be replaced without opening the plug itself, is rated for 13 amps, and is considered by many engineers to be one of the best designed and safest domestic plugs in the world. Most appliances sold in the UK during the last couple of decades have one of these fitted (nowadays usually directly moulded to the cable).

        "The socket with three round pins (possibly in two different sizes!)"

        They're the older BS 546 type which was originally available in 2 amp (small) and 5 amp (bigger) variants. It's rare to see them as standard electrical appliance connectors in the UK nowadays even in old houses, because they've mostly been replaced by BS 1363 types, but they're sometimes used today for centrally switched domestic lighting circuits, where a fused plug can be inconvenient due to being hard to reach and therefore check / change.

        "Also an "electric razor socket" putting out 115V in a bathroom"

        You mostly only find these (BS 4573) in hotels and guest houses so that foreigners can plug stuff in without it blowing up. British consumer and safety laws don't allow 115v items to be sold in general retail (although some specialist devices are available for particular applications), so it's very unusual indeed to find one of these in a domestic setting, especially as they're commonly in bathrooms where UK law requires that sockets of this type be connected to an isolation transformer, thus making them rather expensive. A lot of domestic bathrooms do have two pin shaver connectors, but they're usually C17/E "Europlugs" that only output a standard British 240V/50Hz rather than the BS 4573 type.
    • This guy is measuring a voltage that is higher than our main voltage by twenty volts. Ten volts is plausible but twenty????
    • by DrSkwid (118965) on Wednesday February 07, 2007 @01:51PM (#17923178) Homepage Journal
      Real techies use bare wires and a screwdriver to open ground, remove the screwdriver and the socket holds the wires in place.

      people usually freak out a bit a first but just ignore them :)

  • Don't they run off a low voltage DC supply? What bit of the hardware inside would be upping the voltage to that sort of level? I can't think of anything offhand. Anyone know?
    • by Skater (41976)
      That's what I was wondering, too - the brick converts the power to relatively low voltage DC, so I don't know why there'd be any AC current inside a laptop...
    • by b0s0z0ku (752509)
      What bit of the hardware inside would be upping the voltage to that sort of level? I can't think of anything offhand. Anyone know?

      It's needed to run the electroluminescent panel which lights the screen. ALSO, there can be 19VDC or whatever *between* the adapter + and - VDC pins. But, the whole system could be floating at some high AC voltage in relation to earth ground (as opposed to in relation to one another) if the AC adapter doesn't do a good job at isolation.

      -b.

    • by Em Ellel (523581)

      Don't they run off a low voltage DC supply? What bit of the hardware inside would be upping the voltage to that sort of level? I can't think of anything offhand. Anyone know?
      Its the little noticed but critical part called the SLG (Stupid Lawsuit Generator). McDonald's used to use it in their "coffee" product.

      -Em
    • by Alioth (221270) <no@spam> on Wednesday February 07, 2007 @12:50PM (#17922278) Journal
      The LCD backlight - typically runs somewhere in the region of 150V ac. There will be an inverter in the laptop to produce this voltage.
  • My EE is very fuzzy nowadays, but 65 volts AC root-mean-squared would indicate a higher voltage peak-to-peak. But not as high as 139 volts peak-to-peak. I get 65*2*sqrt(2)=91, but forget if that's even the right way to calculate it. Maybe the 139 volts is a high-water-mark sort of non-repeatable measurement?

  • Right. (Score:4, Insightful)

    by EveryNickIsTaken (1054794) on Wednesday February 07, 2007 @12:31PM (#17921992)
    Sounds like someone broke their labtop and is pissed that Dell won't replace it for free.
  • by Anonymous Coward on Wednesday February 07, 2007 @12:32PM (#17921996)
    Why are individual gripes making it to /.? What is the statistical significance of this observation?

    A single manufacuring defect (if that is the problem) isn't worthy of /.

    Also, did the "friend" modify the laptop at all? Perhaps disassemble it or otherwise "improve" it?

    We've all gotten a lemon at one time or the other.

    Stop griping... get a life.
    • Re: (Score:3, Insightful)

      by Kismet (13199)
      Let's see... Here are the elements required for achieving front page on Digg:

      3rd-hand rumor, preferably from a newsgroup post or blog (check!)
      Personal gripe (check!)
      Conspiracy against the accuser (check!)
      Some sort of advocacy for or against a vendor or company (check!)

      It's the four-point-proof of adolescence!

      And it's coming to Slashdot.

      Or maybe I'm just now noticing.
  • by jandrese (485) <kensama@vt.edu> on Wednesday February 07, 2007 @12:32PM (#17921998) Homepage Journal
    The articles are rather light on details, but I'm wondering if some of these people are using their laptops on a couch and sliding a bit when they sit down? I've had an Inspiron 6000 for a bit over a year now and I've learned in the winter to be careful to set it aside when I'm getting on or off of the couch, lest the static electricity give me a nice zap.

    The fact that he's measuring AC (which is very surprising since the laptops don't have any ready access to AC outside of the power brick AFAIK) make it less likely though.
    • by b0s0z0ku (752509)
      The fact that he's measuring AC (which is very surprising since the laptops don't have any ready access to AC outside of the power brick AFAIK) make it less likely though.

      Screen backlights run on 400Hz AC somewhere between 100 and 200V. Also, if the adapter isn't isolating the laptop from the mains power well, you can get the correct voltage between + and -, but the whole system can be at some AC voltage in relation to earth ground (as opposed to laptop - input).

      -b.

    • Re: (Score:2, Informative)

      by Radon360 (951529)

      You are forgetting about the LCD screen backlight, which is powered from a stepped-up AC supply in the notebook. My guess is that this supply is shorting out to the notebook chasis, perhaps in the screen hinge, causing this problem.

  • threatened him with legal action if he tells people about the problem.

    Why bother? they just have to tell him that, to fix the problem, he just has to touch these two tiny screws there with both hands and power on the machine. Problem solved!

    Seriously though: where is 130V coming from (or is even used) in a laptop? I was under the impression that there's nothing high voltage in there, save for the LCD backlight perhaps?. So perhaps there's a chance that this is all a bunch of crap from some dude who's pissed
  • by Bananenrepublik (49759) on Wednesday February 07, 2007 @12:33PM (#17922016)
    My Macbook has the same problem: whenever it pulls in a lot of current, I get an electrical shock when touching the head of one of the screws. I'm not alone with this problem, there are several threads on the Mac support forums about this, e.g. this one [apple.com]. Of course there's no official statement from Apple :-(
  • My work laptop (an inspiron 6400) has this problem.

    I've been shocked a few times and have gotten memory parity bluescreens at least twice.

    HD has bad sectors too.

    Was already going to call in a support request this weekend when I have time to have the damn thing replaced.
  • Hooray! (Score:2, Funny)

    by aerthling (796790)
    Let the corny puns begin!

    Thank goodness I resisted buying a Dell!
  • My parents had a problem with their garage door opener. Turns out, if you were in your socks (or less, depending on the age of the kids running around) you could get a pretty good jolt from the garage door RAILS coming down the side of the opening.

    Tested with a volt meter, got anywhere between 60-130v rail-to-ground. And it was intermittent.

    Upon unplugging the garage door opener, the voltage went to nothing. So, I asked him "Who wired that outlet?" He responded that he had wired the outlet, and was sure
    • by Animats (122034) on Wednesday February 07, 2007 @12:54PM (#17922322) Homepage

      I know my house was built a long long time ago (1951) and the upstairs, while someone put in grounded outlets, it doesn't physically have the ground hooked up - due to the wiring used at the time of it being built.

      That's an electrical code violation. If you have to have a 3-prong outlet on a 2-wire circuit, you must use a GFCI outlet, which gives you electric shock protection. That's allowed by the US National Electrical Code. The outlet plate should then be marked "Isolated Ground". This warns people that plugging in a computer there may have problems, because it can't dump static and noise into protective ground as usual.

      If you're going to wire up power, read a manual on how to do it. It's not rocket science, but there are very specific rules and screwing up is dangerous.

  • Watch the ESD (Score:5, Informative)

    by Whip-hero (308110) on Wednesday February 07, 2007 @12:41PM (#17922140) Homepage
    For a while, I thought I had a similar problem with both my new Dell laptop, and an old dumpster-diver I had before that. I was getting shocked occasionally when I touched the machines. I initially blamed it on poorly grounded wiring in my house (a rental), until I realized that the problem was electro-static discharge build up from sitting on my Durapella couch.

    I worked it out recently when cold winter temperatures drove the humidity way down. Whenever I got up from the couch I would feel the charge build up, then I would inadvertently discharge myself of a light switch, a metal corner post in the drywall, or worse, on some home electronics. After I accidentally blew out the panel of buttons on a DVD player, I did some experiments. By rubbing my hand on the couch cushions for a few seconds, then using a piece of metal held in my hand (less painful that way) to discharge myself to ground, I found I could jump a spark 2 cm or more. Sometimes, I can get multiple sparks on one charge.

    It's kind of cool, if you know to expect it. And, the remote still works for the DVD player...
  • If my Dell laptop doesn't explode in a shower of sparks and fire it'll instead shock me? Yeah, that makes me want to run out and buy a Dell..

    I'll stick with my old Compaq...
  • About 5 years ago, I was doing IT work, and had to support a bunch of Dell laptops my employed had purchased prior to my starting there. the one in question was an Inspiron, don't remember the model number, but it was probably a P3-800 or so.

    Anyway, the user was complaining about power issues with the laptop - things like it sudenly shutting down, starting up by itself and running the battery down, etc. Then out of the blue, she said, "and it's shocked me a couple of times." Like that's expected behavior.

    I was somewhat skeptical about this, and figured it was a static problem or something unrelated but found out the harsh truth while I was on the support call with Dell. They had me do the usual bonehead stuff like do a hard reset, update the BIOS, remove/replace the battery, etc. I was typing on it and got zapped on the thumb with a serious shock. That's when I noticed the little scorch mark next to the right trackpad button. Looking down through the gap between the button and the case, I could see a little bit of metal from whatever was underneath. Enough charge was building up in there to arc to my hand, which can't be good.

    The Dell support guy heard me yelp when I got shocked and asked me if everything was OK. I told him I just got a nasty shock from the laptop and he said, "can you hold for a minute please?"

    I waited for about 2 minutes, and then some other guy came on the phone and said that they were sending out a replacement overnight and that I should return the other one right away. The replacement was a top-of-the-line Inspiron for the time, quite a step up from the one that zapped me. I figured it was a pretty good response.

    So I issued the user a new Thinkpad from our closet and kept the nice Dell for myself. It worked out for everybody.
  • by neo (4625)
    My laptop shocks me all the time. I thought this was a feature to keep me awake on long flights.
  • Perhaps is an as yet unannounced joint venture "feature" that Dell is not allowed to disclose, yet?

    http://yro.slashdot.org/article.pl?sid=07/02/04/22 16219 [slashdot.org]
  • by Buran (150348) on Wednesday February 07, 2007 @12:44PM (#17922210)
    "Dell has tried to keep him quiet about the problem and has even gone so far as to have him banned from a few websites, and threatened him with legal action if he tells people about the problem."

    On what grounds would this be a valid case? Once you sell something to someone that they own (not license), you cannot tell them what they can and cannot do with it so long as you do not cross any other lines and violate someone's privacy (which is why I suppose selling stuff you bought at auction from a storage company is illegal -- although I think most of what those guys did was OK, and the judge overreached). So this guy has every right to say "My computer shocks me, here's what kind of machine it is" because it's not slander, it's the truth.

    Seems to me like this guy can file under anti-SLAPP rules, can't he? This company is trying to shut up someone who is exposing their mistakes -- and yes, it is a valid complaint (why wasn't he given a grounded power supply when it is known that failing to ground electronic devices can shock users?) and yes he has the right to be publicly heard if he wishes to. No one has the right to not be offended by what he has to say.
  • by trailerparkcassanova (469342) on Wednesday February 07, 2007 @12:56PM (#17922354)
    He needs to have a good ground. He's using the metal case of another PC as ground so he might just as well be measuring the voltage off the PC case.
  • by Animats (122034) on Wednesday February 07, 2007 @01:09PM (#17922580) Homepage

    The article is vague. It's not even clear if the problem occurs when the laptop is not plugged into the charger. The power supply for some backlights can produce over 100v, so there is a potential shock source even on battery power.

    If the problem is related to the charger power supply, that's a clear safety hazard. Check for a UL logo, and go to the UL web site [ul.org] to check on whether the power supply actually has approval. If the power supply is made in China, it must have a hologram UL sticker with the UL approval number. There are power supplies out there with forged UL approvals, and UL is trying to crack down. (Those are the power supplies that fail in power supply tests on PC websites. UL tests them loaded up to their rated value and runs them for hours at full load, so the UL logo means it really can deliver whatever power it's supposed to deliver.)

    • Re: (Score:3, Informative)

      by drinkypoo (153816)

      The article is vague. It's not even clear if the problem occurs when the laptop is not plugged into the charger. The power supply for some backlights can produce over 100v, so there is a potential shock source even on battery power.

      The typical modern CCFL backlight requires 1200V to start up and runs on 400V. The amperage is fairly low.

  • by Red Moose (31712) on Wednesday February 07, 2007 @01:14PM (#17922656)
    I just tried to click the link and it said Internet Explorer cannot display the webpage!

    Michael Dell doesn't fuck around does he!!!!

  • Verified (Score:5, Informative)

    by mrfunnypants (107364) on Wednesday February 07, 2007 @01:28PM (#17922856)
    I just checked all the Dell laptops our company owns, about 10 of them (E1505 and E1705 models). All of them are producing around 3-5 Volts of AC off the screws. In fact the one producing the highest voltage is currently on a service call as the system has stopped working.

    I am currently in contact with Dell about this issue and I am being informed they are letting the engineers know of the issue and hope to have a resolution soon.

    The funniest thing I have read regarding this was a post in notebookforums from aindfan:

    "I took my E1705 up to the Senior Design EE lab here. The two seniors that were there glanced over at my oscilloscope and realized what was going on, most likely assuming that I did not ground properly. When we took it over to the new, more advanced scope, the measurements reported were of a 60Hz periodic function with a peak-to-peak voltage of ~150V.

    Being curious EE's, the next natural step that the seniors suggested was to see if we could pull any current out of the screws. A few moments later, we had a circuit with a laptop screw connecting to an LED in series with a 1K Ohm resistor connected to the ground node of a power supply (connected directly to the ground of a wall socket). I am happy to report that the LED turned on and there was a measured current of about 1.4 (mille or micro, I forget which) Amps flowing from the screw to the resistor.

    Remember, folks, there will never be current flowing out of the laptop without a load attached to the screws. So don't hook up any 1 Ohm resistors if this is happening to your laptop, you might fry a few things (due to the large current, remember V=IR).

    I'm opening up a Dell chat now to see about getting this resolved.

    Thanks for starting this thread ViriiGuy. It was quite interesting to play around with the testing for this.

    EDIT: When I asked the dell chat support tech if she could send a 3 pronged power adapter (after I explained the issue), she replied "I cannot do that.""

    Good stuff.
    • Re: (Score:3, Informative)

      by mrfunnypants (107364)
      I have been testing this issue more while on hold with Dell's technical support.

      If I disconnect the AC adapter and test the screws again the voltage essentially disappears. From what I have read on other forums the issue seems to be that the AC adapters supplied by Dell are two pronged, no ground, and if you use a three pronged adapter the issue is nonexistent. From my test this seems to support this conclusion.

      If you have a E1705 or E1505 I would suggest calling Dell and discussing this with them as I have
      • Re: (Score:3, Interesting)

        by Andrew Sterian (182)
        Most modern laptop power supplies are isolated switching converters, which means there really should be NO electrical path for current to flow from the AC outlet to the laptop since a transformer isolates the two sides. If you can indeed draw current from the chassis ground of the laptop itself to the earth ground, then I'd say the laptop power supply has a serious flaw.

        Switching to a grounded adapter supply may have just fixed the problem by switching to an adapter that is properly constructed.

  • by sd_diamond (839492) on Wednesday February 07, 2007 @01:53PM (#17923200) Homepage

    But I think that Slashdot editors should conduct themselves in a more professional manner. How else can we expect you to discharge your duties effectively, and eliminate the audience's natural resistance?

    Now let's get back to the current topic.

  • by Ancient_Hacker (751168) on Wednesday February 07, 2007 @02:38PM (#17923844)
    Every power supply is required to have two capacitors from each side of the power line to ground, and another capacitor from ground to output ground.

    Now if you hook a typical $4.99 digital voltmeter from Harbor Freight, the input impedance of the voltmeter, combined with these capacitors, will indicate anything from zero to 377 volts.

    And if you rub your cat, the voltage could go much higher!

    As you bright folks out there may be guessing, it's not the voltage so much that is the problem, it's the current. And the current is miniscule, microamps.

    So no conspiracy here, move along, etc....

    • The problem is that even if the current is miniscule, humans can feel as little as 1 mA. The LED lighting incident commented on earlier shows that the current is at least 1 mA, if not more.

      The issue is that a laptop shouldn't be leaking any current. None. A circuit designed as you suggested is a potential lawsuit - if a capacitor shorts, the user gets full line current - not a very good idea. A person can be electrocuted well before a circuit protection device trips.

      • Re: (Score:3, Informative)

        The issue is that a laptop shouldn't be leaking any current. None.

        Almost all devices which utilize wall-operated power supplies can have leakage current associated with them.

        A circuit designed as you suggested is a potential lawsuit - if a capacitor shorts, the user gets full line current

        Dropping a laptop on your toe is a potential lawsuit. The capacitors mentioned by the other poster are called X and Y caps. Any transformer-coupled switching power supply will electrostatically couple energy from the

        • Ever? (Score:3, Insightful)

          by phorm (591458)
          Of course they can fail. Solder joints can come loose, the capacitors themselves could have a undetected defect that becomes more apparent over time. As for factory testing, in a perfect would we could be sure that every one of the millions of units sold had every component that should be tested checked out properly, but the facts of life say that sometimes this doesn't happen, either due to accident, equipment issues (faulty testing/manufacturing equipment), human error if applicable, and even due to *gasp
    • Re: (Score:3, Interesting)

      by BillX (307153)
      It's true that floating a cheap DMM's leads in the air (or even a very good DMM's) will show all sorts of spurious voltages, and that the "AC" voltage is not true RMS unless the meter says true RMS on the package... but users feeling a definite tingle through their skin indicates to me a problem, as does the demonstration (assuming it's true!) of pulling a milliamp over 1k off the "floating" case.

      (Yes, IAAEE, and yes, one of my current [no pun intended] projects involves developing a device to zap humans -
    • Re: (Score:3, Informative)

      by Prune (557140)
      WTF? As one comment already explained, the problem only occurs when ungrounded power adapters are used. Three-pronged plug grounded ones remove this problem. So clearly it's not the issue of the EMI filter you described. As another post explained, the issue is capacitive coupling between the primary and secondary windings in the switching transformer. I am sorry that your misinforming post got moderated highly.
  • by BigBuckHunter (722855) on Wednesday February 07, 2007 @04:22PM (#17925234)
    The article is a bit barren, but the comments have some gems. Like this.
    I have a dell 6400 with the better display and YES i do get little shocks every other time i touch it. I thought its ok, but i guess its not...should i call dell and address this problem?
    I mean, holy f'ing 5h1t! How can anyone possible have to ask someone else that question.. Errr, Duhhh... My laptop is shocking me Bob... Should I call support?

    I'm just astounded.
    BBH

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