Latent defects from electrostatic discharge,

Hi, with an electronmicroscope you can check the die. If it was destroyed due to ESD, you can see this. A "before and after" foto can be found at:

Also read what they say about AMD.

Without advanced equipment, it is very difficult to tell the cause.

Pieter

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What I fail to see is how the most extreme conditions in the original HV discharge can fail to produce any immediate defect but produce a latent defect that only becomes a full defect, at some later date, in normal service conditions of voltages and currents.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I would guess from the photos that I've seen of this damage, that only part of an internal structure is blown away such that the manufacturing tests don't pick it up as being out of spec in any way. Imagine if a particular transistor was designed into the chip to be part of say a clock oscillator, and one of the connections to it gets partly blown away due to an ESD on an external pin. The connection might now be so thin that under the constant stress of the oscillator current flowing in it, it might heat up more than it was designed to, until eventually, it fractures and voila ! no clock and the chip completely dies. As far as proof of this, I think it has been shown pretty conclusively by s.e.m. photos, as Pieter says, that it is a very real effect. I seem to remember that some years ago a plane crash, or maybe one that was shot down accidentally or something along those lines, was shown in the subsequent investigation, to have suffered some kind of navigation equipment anomaly, that was caused by an ESD damaged chip. I could be telling utter lies there, but I'm sure that something like this is in the back of my mind amongst the cobwebs that seem to settle there a little more every year ...

Arfa

Personally, I'm extremely skeptical of the ESD goblin, particularly in latency. I think the horror stories have been greatly exaggerated, at a minimum. But, I have no scientific data on which to base my skepticism.

Yes, it really does happen. The leakage current on the input may be specified as 1 nanoamp or some other value relevent to the geometry or materials involved. An electrostatic dischange that doesn't distroy the device may cause the leakage current to jump in the hundreds of microamps. This current can be easily suppled in most cases by the driving device. However, in such small structures, a phenomenon called electromigration can take place. The many microamperes of leakage can cause metal migration to take place along the leakage path. Eventually it leads to a sufficiently low resistance that the driving source cannot supply the current to change the logic state. Then you have a failure. It may take days or years depending on many factors.

Al

After 44 years at Bell Labs, and head of the Bell Labs EMC Committee for many years, there are ESD effects at the atom level that lead to failures in later times, due to disruption of the normal atomic crystalline (SP?) structure. I wish it wasn't so, but it is.

H. R. (Bob) Hofmann

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Any idea of failure ratio, due to ESD damage, causing immediate failure and proportion due to delayed latent failures ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

If you Google latent esd you will find about 75000 hits. It sorta hard to pick out the relevent ones. Good luck!

Al

When I worked at a computer company, if ever a PC came in for Lightning Damage, and the Insurance company INSISTED only replacing the damaged parts (instead of replacing the whole machine), we put in a disclaimer saying that Latent damage resulting from that strike may cause other components to fail later. And Guess What, They usually always failed within 3 to 6 months.

Well how do you go about repairing a pc thats been hit by lightning??? Just replace everything except the case?

"Michael Kennedy" wrote in news:SOadnfRbx9V_sIjanZ2dnUVZ snipped-for-privacy@comcast.com:

Surely depends on how direct the hit was. A direct one would induce currents that would blow the case apart violently from magnetic repulsion.

As for damaged parts, I guess the answer is to zap the lot afterwards just to keep the insurance company honest.

A great way to scam a new HDD or monitor?

Best regards, Spehro Pefhany

Insurance would only pay to replace the items that showed physical damage (normally modems, PSU's and monitors.

I managed to get myself several modems and monitors that were easy fixes (normally opto on modem, HOT on monitor, sometimes even fuses on monitors). Just cos the insurance didn't want them after the claim.

"Peter K" wrote in news: snipped-for-privacy@saix.net:

This is why I never pay for insurance.

And I DO mean never, apart from a brief period a few years back paying for life and injury insurance. The whole point is meant to be trust, sharing of the load in cases of loss, but the entire industry is founded on profit and distrust.

If a computer worked, then after a nearby lightning strike it does not, and can easily be shown as not able to pass a POST or show any other seign of life, the insurance company must either accept that they are liable if it was insured against lightning strikes, or accept that people are not wrong to refuse to accept their'services' and therefore not pay for them.

I'd rather put my money steadily into small assets than can be easily reconverted to cash fairly quickly at a decent rate. I could lose them, or my life. So long as I did not lose both, either I, or someone else close enough to me, will benefit in some way. The worst case is very serious injury combined with loss of all assets. That's very unlikely, and even people who get everything 'right' can't immunise themselves against that if it happens.

The whole problem with insurance comes from a situation where people want to believe they somehow cannot lose. That, coupled with the fact thet they are ALWAYS losing the moment they start paying premiums, is absurdity. It's bad enough that we are sometimes forced to do this by law if we want to drive or own a house, but there's no point in encouraging it.

If someone knows electronics well enough to handle their computers and other tech stuff, where is the sense in trusting crucial decisions about that stuff to people who don't, and whos primary motive is profit, or at least retention of what they now see as their assets?

It's all very well saying that the small amounts from many people cover the high cost of unlikely events, but what possible use is that if they won't pay out when the shit hits the fan?

/rant.

Maybe. But that is not my experience from the early '80's, for whatever that is worth.

We had a major thunderstorm that took out the phone company and cable TV company equipment at their offices, and wiped out most of the electronics in our neighborhood. I had an Apple II at the time, which was destroyed, but with no visible physical damage. A bunch of other stuff was killed in my house, too, including the cable box and a cordless phone, both of which had to be replaced. I fixed the rest, but the Apple was totaled. The insurance company required a repair estimate from a local repair place. They said it was not repairable, so the insurance paid for a replacement PC. I suppose they recognized that there was no way they could deny the claim, with all the damage in the neighborhood and at the phone company and cable TV offices.

Ed

Besides the other causes mentioned in this thread, it's also possible (though I don't know how commonplace) that the initial strike destroys the protection diodes (shunts to power and ground) but not the IO transistor itself. So the circuit functions normally but has no more ESD protection; a subsequent (unnoticed) static event at lower voltage then takes out the transistor.

TM

Gallagher on life insurance: You're betting that you're going to die - you lose either way!

TM

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@e34g2000pro.googlegroups.com:

Nice. Another way of looking at it, the house always wins. Ok, it might not be exactly the same as a casino but the similarities are shocking. First duty is to preserve the house. Second duty is to honour the winnings of the ordinary punter. Third duty is to try to minimise the unusual demands especially those which conflict with the first law. Sounds almost as simple as Asimov's Laws of Robotics, and it is. Anyone who has really been hit hard by injury knows that the insurance people never pay enough to cover, the promise is always vastly outpaced by the reality. Most people with really severe needs are more likely to be funded directly by the heath services as the results of the unusual procedures directly benefit them as well as the patient. Agreements like that usually begin after the insurance payouts have long since failed to cover.

It won't be easy in many cases to work out what is the best way to do what insurance promises to do, but with the growing problems with insurance (another instance made national news on the BBC this evening), people will start to keep their money more carefully instead of spending high and payting what's left to other people for what amount to promises that can't be kept.