01-28-2009 09:34 AM
or at least this is the only thing that comes to my mind. Compaq presario v2040us served us for quite a while and yesterday night my wife called me that laptop has shut down and won't turn on. No lights, no noise no matter what you do. This happened when she walked to the laptop and put her hands on the keyboard to start typing. She felt a weak discharge between her fingers and the keyboard (I suppose something metallic that is under keyboard, actually) after which the laptop died. It's winter time there, lots of wool close, heating + dry air. The static discharge between you and all the metal staff around (including computer) is a common thing, but it never was causing any problems until this time. This is especially surprising, since the device was powered through the ac-adaptor, and I would expect this thing to be grounded.
Did anybody hear about such things before? What potentially can go off? Is it worth repairing (in terms of money) or should we start watching the deals for the new one?
01-28-2009 01:12 PM - edited 01-28-2009 01:15 PM
Its poss. to kill it with low shocks, but if it was plugged into the wall AC grounded then I doubt it. Since the Base of the keyboard is grounded to the other grounds, then grounded to the Power Brick, per UL testing.
It may have overheated "Processor". common for having no Power "DEad" condition Processor is replacable.. . You need to start pulling hardware and see if you can get it to Bios Post.
Start easy, Replace ram with ram you know works. or borrow some. IF you have two sticks try each one by itself.
Check your Output of the Power Brick and the Connection in the back. Wiggle it around too.. Use a Volt / Ohm meter and see if its got the correct voltage thats listed on the brick. 19 volts etc.
Pull Hard drive out.. You dont need it to POST.
Pull CD DVD drive out, You dont need it to Post.
Any other hardware etc..
Need Processor, Memory and Motherboard to get to the Splash BIOS screen. Once you get it there, Your golden!!
01-29-2009 07:19 PM
02-07-2009 05:50 AM
02-07-2009 07:57 PM
I simply disagree, with everything you said, and here are the reasons.
It sounds highly unlikely that this was caused by static dispite the conditions you mentioned! If your wife had built up a static charge this would (should) have been discharged through the chasis away from the sensitive components.
I learned though my life that the world is not perfect as well as stuff around us made by people . Just googling for "laptop static electricity" keywords you'll see how many models from various manufactures have all kinds of problems with chassis and internals not being properly grounded. How simple touch to speaker grill or usb port shuts down or crashes the system. Even though, to be honest, I did not find a single case reported when the machine totally died.
I can't see how a static belt would have made it to static sensitive components
therefore the laptop not working afterwads was either coincidense
I can admit that
or there could be a short circuit to your chasis.
I guess you refer to mechanical short circuit. Yes these things happen, but in order to initiate one (assuming it is inside) you should physically act on a device (press on it, shake it, flip it etc). Approaching the keyboard with your fingers does not seem to be enough, unless you have some kind of telekinetic abilities. Note, that this a laptop, a portable device which is being carried to work and back on a daily basis. She simply puts it into sleep and shoves it into a backpack, and no problems have been observed so far.
If there is a short circuit your wife can expect more shocks and more problems with the laptop. IMO there is a good possibility this was the belt that your wife received.
there is is such thing called electrical insulation. The materials which do not conduct electric current protect you from being shocked. The keyboard of this particular model (as well as most of the devices I saw) is made of nonconductive plastic, and has no metal parts exposed. There is no way you can be shocked from the laptop unless you have some metal part under the keyboard under extremely high electric potential (order of kilovolts). Considering, that a maximum voltage out of a power supply of the most modern laptops is ~20V, and most of the laptop don't have any ridiculously huge capacitors inside -- this is highly improbable. On the other hand your charged body can easily accumulate and carry a potential of several kilovolts due to simple walk on the rug in relatively dry environment. Thus, when I hear that a person felt an electric shock just before touching the subject of discussion I see only one way for this to happen.
anyhow. the device is back to life and there's been no complains for more than a week, and it's all that matters.
02-08-2009 07:02 AM - edited 02-08-2009 07:09 AM
Take it from an electrical engineer!! The chances of your laptop being zapped by STATIC in those circumstances are extremely low if not nonexistent.
Static electricity builds up on a person and when that person touches something which has been properly earthed ie the chassis to your laptop, the STATIC electricity ceases to be STATIC and discharges through the chassis directly to earth sometimes causing a small shock and no harm to components.
Now then, if the chassis is short circuited to a LIVE component or if by leaning, or pressing in the right area causes the chassis to touch a LIVE component and somebody touches the chassis then that would cause a shock AND possibly affect the component that shorts to earth likely causing the laptop to malfunction.
The reason Chassis are earthed is to,
1) Discharge static safely to ground without affecting static sensitive components.
2) In the event that bumps, knocks, bangs etc cause some LIVE component, wire or connector to be dislodged and to touch a conductive part of the chassis then that LIVE electricity will be directed to earth lessening the chance of shock.
The ONLY way STATIC electricity could zap your laptop was if you physically touched a static sensitive component (generally a chip or cct board) without either an antistatic wristband or earthing yourself prior. As you state that it was plugged into the mains then that is the route any static would take. As already stated Static will find the shortest route to earth, hence why metal on electrical products always have a little green and yellow lead connected internaly.
The world we've created may not be perfect, but the laws of physics are. On the subject of imperfection, I hardly think that "Google" is the authority on electrical safety. Speak to an actual person who KNOWS what they're talking about and they will confirm what I have told you. Google - a great tool but subject to the imperfections you talk of.
“I guess you refer to mechanical short circuit. Yes these things happen, but in order to initiate one (assuming it is inside) you should physically act on a device (press on it, shake it, flip it etc)” - As you so helpfully point out it’s a portable device and subject to bumps knocks etc. so it is more likely than most products to develop a loose earth or to create a chassis earth.
“there is is such thing called electrical insulation” - Basically this is my point! Insulation has possibly broken down at some point and caused live to touch earth!
“There is no way you can be shocked from the laptop unless you have some metal part under the keyboard under extremely high electric potential (order of kilovolts)” - Or the insulation has broken down causing a short to somewhere else on the chassis which your wife was also in contact with.
“On the other hand your charged body can easily accumulate and carry a potential of several kilovolts” - Agreed! But that voltage is directed to earth away from sensitive components. If that process fails then there is very possibly a more serious issue. By the way technically 20V DC has the potential to cause a pretty serious shock if your wife's resistance is 1000 Ohms (she'd probably have to be soaking wet in bare feet and stood in a pool of water for that to happen, but still...) that makes a current of 20 mA. Try goggling the potential affects of a 20mA shock I wonder what you'd find...! The voltages used within the laptop are actually less than that. 5V and 3.3V if my memory serves me correctly. It is unlikely to result in any serious harm but at the very least its unpleasant and will cause problems with the laptop... It may simply be a loose connection or it may have been a one off... Who knows?
For the record I've worked on computers since I was 12 and I've been working with static sensitive components professionally for 10 years, I do know what I’m talking about. Take my advice or leave it, but if you’re going to question it find someone/thing that is a little more reliable than Google to base your wife’s safety on.
“anyhow. the device is back to life and there's been no complains for more than a week, and it's all that matters.” Till next time???
02-08-2009 08:56 AM
thank you for bothering yourself with such a long answer but this discussion loses point to me. I've already mentioned the flaws in your argumentation, but you do not seem to take these into account. So let me repeat myself:
1) you do not have to physically touch a metal object to initiate the static discharge between it and your body. Approaching the object of the electric potential lower than your body to the distance when the electric field strength is higher than ~30 kV per cm (the dielectric strength of air quoted in multiple respectful sources) is enough to ionise a conductive channel. (fundamentals of electrodynamics). Metal object does not have to be grounded to zap you, even you table spoon will do it. You never know what are the defects in design made by manufacturer, and which sensitive component of the laptop is closer to your body, the grounded one or something else .
2) 20 volts from your laptop (this is the actual the voltage from most laptop power supplies, which is then reduced to your 3.3 and 5 volts ) or 12 volts from your desktop will not zap you. As you mentioned you body simply has too high resistance for it. Although, it sometimes works if you try it with the tongue. However my wife did confirm that she felt an electric shock (as well as the sound from it).
and speaking about google, you seem to be missed that I did not quote it as authority in electrical engineering, but solely as source for statistics on devices failure rate, on which I do acknowledge it as authority.
So please take all of the of the above from somebody who is holding a masters degree in electrical engineering, a PhD in condensed matter physics and been working with computers for almost 20 years now (I'm sorry, but you are the first one who started posing here with your credentials).
PS: things don't become more true if you write them in OBLIQUE CAPITALS.
02-08-2009 02:47 PM
So you, with your Masters Degree in Electrical Engineering decided to post on a website, likely to attract answers or suggestions from people considerably less qualified than yourself... Hmm, strange surely someone with those credentials would be the ideal person to answer a question such as yours?. Then when someone does come up with a suggestion or advice you chose to disregard it based on flawed "knowledge" and google searches... Well done. To add insult you claim to have a PhD in whatever that is... OK... those first posts were not written by someone with a PhD in anything, the grammar was awful, the facts were wrong and any good Dr would know that Google, as good a source of information as it is, is only as powerfull as the opinions that you happen to find.
One last time Static did not zap your laptop and cause it to fail. Quoting from Google sources of electrical theory, or however the hell else you came up with those facts does not make THAT any LESS true! A static discharge may well have occured but only to earth, causing no problems to the laptop. Or else it was a short circuit that did cause the problem you mentioned. But you holding your Masters Degree and 20 years experience knew that already.
Good luck Mrs. atenrok I think you'll need it.
02-09-2009 02:02 AM
those first posts were not written by someone with a PhD in anything, the grammar was awful,
my bad. Should have apologized for my language right from the beginning. But you, dear friend, should have noticed by this time that English is not my native as well as the others three languages I'm fluent in. But that's irrelevant to the subject. If you want to go personal -- the email address is in my profile, no need to bring this crap to the public. Maybe I'll manage to explain you somehow why people like me care about opinions from general audience.
01-07-2011 10:46 AM
I have an Pavilion dv7-1129wm, and it started to give off mild to very noticeable electric shocks when you touched the keyboard, anywhere around the outside of the unit, usb ports, etc. I contacted Hp and also checked the Net for possible causes and if other people were having the same issue with this unit or any HP Laptop Units(Also the warranty expired a several months before these things happen on 2/5/10). I sent the unit in to HP for the technicians to check the unit and they are saying it is working in acceptable limits by way of their 'HP Health And Safety Person.'
I have also worked on all models of laptops and PC's since I was about 18 years old and I don't think the risk of an electric shock is a normal thing during normal use regardless of how small, but in my case they were turning severe. Severe, meaning, they had begun to affect the OS, and any devices you would connect to the PC. These effects were displayed by the system rediscovering and losing the device while the unit would just be sitting idle. Noticeable by the sound of the system chime that most Windows systems use when making connection to a added device.
My OS had started to receive startup errors and I had to use restore to get back in the system, which meant something was happening inside the unit itself (Using Windows Vista 64 Bit). I stopped using the unit even before I contacted HP in-regard to this problem. I removed the HDD and connected it to my Desktop unit to remove all important information (I am a trained Tech, familiar with several ways to do this and I have several devices to do this quickly. This said without titles and stuff like the other guy).
I find it strange that the 'HP Health And Safety Person' told me right from the jump, that this problem has been a problem of "Improper Grounding" even before the unit even left my home. They felt very comfortable speaking as a HP Engineer when placing fault on the user or the user's home, but when asked questions about 'other' possible system problems, they quickly stated they were not an engineer. If the 'Improper Grounding' was indeed a problem most of the electronic equipment I have in my home would not work even if connected to the most expensive surge protection devices, which I have several of them in my home.
Anyhow, the Contact person is already making plans to return the unit I believe as is, cause the "Engineer's" have found all voltages are within safe limits, whatever that means? I called her back but have not received a return call yet, but I will post here the conversation highlights. I also have a forum to let people know not to buy these products if this is indeed the surprise you will receive once your warranty expires or if they don't want to admit this model has a defect. I think this is on of the quickest testing periods I have ever seen, seeing that I had up until Jan 8, 2011 to get it in. I guess I have no choice but to await my high-end Tesla Coil to return.