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Dell Laptops Have Shocking New Problem
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."
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.
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...
--WH--
"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.
i am a soviet space shuttle
But this guy says he measured his voltage with the multimeter on AC. Static electricity is the buildup of charge on something capacitive (like you and me) and would be measured as DC. That is, if you could measure it at all, since we make pretty bad capacitors and any ordinary multimeter would quickly drain the charge away.
I am not a crackpot.
The LCD backlight - typically runs somewhere in the region of 150V ac. There will be an inverter in the laptop to produce this voltage.
Oolite: Elite-like game. For Mac, Linux and Windows
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.
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 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.)
Pretty easily, when it's full of voltage converters, and a high-voltage inverter to run the LCD backlight,
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.
"Real knowledge is to know the extent of one's ignorance" -Confucius
Rubbermaid.
Called them up twice because one of their guaranteed for life tupperware container cracked in my dish washer on 2 separate occasions (similar size/type). They apologized, suggested putting them on the upper dishwasher rack to reduce the chance of this happening, and sent me a coupon good on anything rubbermaid up to the value of the thing that broke. I asked how I needed to send in the broken container (which their warranty terms say you have to do), and they said I didn't have to because they trusted that I was telling the truth.
Otherwise, never had a problem with any of their stuff and the only remotely bad thing that I know of that they did was try to get retirees of a company they bought to pay $40/mo for health insurance.
I had the same problem. Chances are your laptop is overheating. Get a fan pad. They're powered off of one of your usb ports and keep your machine a lot cooler.
I recomment Vantec's LapCool series, and at about $25 they won't break your wallet.
Everything I need to know I learned by killing smart people and eating their brains.
I didn't RTFA, but in countries like Switzerland, we have regular wiretestings. You're obligated to do them, if you don't do them, you will get disconnected from the Grid.
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....
Actually that won't happen. If the laptop is running on batteries there won't be a closed loop through the bath water. The current has to flow from one pole of the battery through your body and back to the other end of the battery, preferrably after having the voltage multiplied a few times. If you are getting shocked from a self-powered laptop the route is probably from one part of the chassis to another, so grounding your feet in bath water won't make much of a difference.
"Will future ages believe that such stupid bigotry ever existed!" -- Ivanhoe
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 primary of the transformer, to the secondary. This energy can result in lots of signal integrity related problems in the connected equipment, as well as EMI/EMC issues. In order to minimize these problems, a ceramic capacitor is connected from one leg of the primary, to one leg of the seconday. It gives a return path to the coupled energy. These capacitors have a UL listing that is separate from that of the power supply. They don't fail. Ever. They have a rating of almost 4kV, and are hi-pot tested to that at the factory.
I think it would be nice if the slashdot crowd learned more about the toys we hold so dear. It's worth knowing.
Also, DMM's are very high-impedance, you can measure 'dangerous' voltages by just holding the leads in the air. Like any piece of lab gear, it's nice to know when you can believe it's output.
I'd like to submit Logitech to the list!
I purchased one of their MX1000 laser mice when it was a brand new item, and while it was excellent - my 4 year old dropped it on the floor one too many times. The center rocker button surrounding the scroll wheel started sticking occasionally, causing things to scroll, out of control, in web browsers, MS Word, etc.
Seeing it was under Logitech's warranty, I figured it couldn't hurt to give them a call - to see if they might be able to sell me a used/refurbished replacement mouse inexpensively or something, given the circumstances.
Instead, the sales rep. looked up its serial number to confirm it was under warranty, and simply said "A brand new replacement is on its way." I asked if they needed the old mouse back, and I was told "No. You may as well keep it to have a spare charging base or something." Within a week, a new mouse was at my doorstep, in the retail packaging!