Advice on testing for lightning damage/ power surges

Discussion in 'Hobby Electronics' started by ForensicOke, Oct 24, 2003.

  1. ForensicOke

    ForensicOke Guest

    BlankIs there anybody out there that can provide me with some advice on the testing of computer equipment for traces of lightning damage/ power surge damage? We test computers for the insurance industry when a claimant makes a claim regarding "lightning damage/ power surge damage" to computers and computer peripherals.
     
    ForensicOke, Oct 24, 2003
    #1
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  2. ForensicOke

    Oldus Fartus Guest

    In news:bnbfqr$mhe$,
    ForensicOke <> wrote these words:

    | BlankIs there anybody out there that can provide me with some advice
    | on the testing of computer equipment for traces of lightning damage/
    | power surge damage? We test computers for the insurance industry when
    | a claimant makes a claim regarding "lightning damage/ power surge
    | damage" to computers and computer peripherals.

    In about fifteen years of computer servicing I have only come across a
    handfull of lightning damaged computers, and of those several have
    exhibited very clear signs of damage. One was quite spectacular with a
    hole burned into an internal modem where several components just
    disintegrated, and another showed signs of damage around the serial port
    on the motherboard. In a couple of other cases I have been able to see
    no clear signs of any damage, and could only rely on anecdotal evidence.
    (For example, the day after a severe thunderstorm someone brings in a
    computer which stopped working during the storm.) Thorough examination
    of the motherboard may show signs of damage to some of the circuit on
    the underside of the board, or there may be no damage evident at all.
    I have only once been asked to give an insurance statement regarding
    lightning damage to an external modem, and was quite happy to do so, as
    my own external modem had been damaged the same day during a storm.
    (Incidentally, that was the only time I have had such damage to my own
    computers.)

    Power surges may cause similar damage, but more often than not I have
    found any damage to be in the power supply - I can not recall any case
    where there has been motherboard damage which could be attributed to a
    power surge.

    Obviously my experiences may be different to others. I live in an area
    which is not particularly lightning prone, and which has a relatively
    stable power supply, so I can only suggest you rely on gut feeling in
    the absence of any hard evidence of damage.

    --
    Cheers
    Oldus Fartus
     
    Oldus Fartus, Oct 24, 2003
    #2
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  3. ForensicOke

    Rod Speed Guest

    Blank
    ForensicOke <> wrote in
    message news:bnbfqr$mhe$...

    > Is there anybody out there that can provide me with
    > some advice on the testing of computer equipment
    > for traces of lightning damage/ power surge damage?


    The only thing thats really feasible is a visual inspection
    looking for obvious stuff like pcb traces blown off etc.

    With the lower level stuff that doesnt produce that, it can
    be quite difficult to separate power surge damage from
    just a power supply failure/bad design that sees the failing
    power supply kill whats powered from it when it fails.

    > We test computers for the insurance industry when a
    > claimant makes a claim regarding "lightning damage/ power
    > surge damage" to computers and computer peripherals.


    The short story is that there is no rigorous definitive testing feasible.
     
    Rod Speed, Oct 24, 2003
    #3
  4. ForensicOke

    Ken Taylor Guest

    BlankAs with the other posts, there isn't any definable thing to look for. I've had motherboards from Darwin which died after near lightning strikes and there was no indication other than no-go.

    Did you have any methodology in mind when you offered to test for the insurance industry?

    Ken
    "ForensicOke" <> wrote in message news:bnbfqr$mhe$...
    Is there anybody out there that can provide me with some advice on the testing of computer equipment for traces of lightning damage/ power surge damage? We test computers for the insurance industry when a claimant makes a claim regarding "lightning damage/ power surge damage" to computers and computer peripherals.
     
    Ken Taylor, Oct 25, 2003
    #4
  5. ForensicOke

    ForensicOke Guest

    I just want to thank you guys for all the info and response to my question.
    We are working through all the info we got from you and really appreciate
    it!

    Thanks again!


    "Rod Speed" <> wrote in message
    news:bnegv3$vmj15$-berlin.de...
    >
    > ForensicOke <> wrote in
    > message news:bndac3$2m8$...
    >
    > > I'm a newbie and is still learning along the way.

    >
    > Then you had better watch out 'certifying' whether something has
    > got damaged by a power surge for an insurance company. You
    > may very well end up with your arse in a sling if you dont watch out.
    >
    > > Thanks for all the answers and advice. My collogues
    > > were right, I should have joined this newsgroup long ago!

    >
    > > Furthermore, I would like to know if there is a way to differentiate
    > > between a power surge not caused by lightning and a spike caused
    > > by lightning by testing the components on the motherboard?

    >
    > Nope. No testing of components on the motherboard can
    > ever show more than the power supply did over voltage
    > the supply rails. It can never distinguish between a badly
    > designed power supply failing and doint that as it fails and that
    > being due to a power surge getting thru the power supply.
    >
    > It isnt normally going to be possible to work that out even from
    > the power supply itself except in the most extreme situation like
    > say 11KV or 33KV ends up on the 240V mains for a short time
    > and blows the shit out of the power supply in the process.
    >
    > And thats fortunately a very rare occurrence. And is best
    > worked out from what other houses on that 240V line also
    > experienced damage to electronic devices at the same time, and
    > other electronic devices on that 240V line in the same house etc.
    >
    > > I know that there is a difference in change over time
    > > between normal power surge and surge caused by
    > > lightning (transient much faster in nanosecond)

    >
    > Thats not necessarily true once its on
    > the 240V line coming into the power supply.
    >
    > > and was wondering if that perhaps can in some way give
    > > an indication on the components which of the two it is.

    >
    > In theory its possible because very fast rising edges like that
    > can give the weirdest results on what gets blown and what
    > doesnt, basically because the very fast edge tends to follow
    > the path of least inductive/transmission line impedance, but
    > unless the over voltage is extreme enough to blow tracks
    > right off, there isnt normally anything visibly fried.
    >
    > And it can be surprising what survives known very high
    > over voltages and doesnt die, at least not immediately.
    >
    > > We have tried signal tracking but that can only give
    > > an indication of a good, bad, or marginal components
    > > on the mobo and does not help very much.

    >
    > Yep, and cant possibly distinguish between a power supply that
    > has just died and fried stuff powered from it due to bad design.
    > In other words it just died without there being a power surge.
    >
    > > Normally we check for lightning activity via the Weather Service in the

    area
    > > stipulated by the claimant as place of loss, but remember we are in

    South
    > > Africa! The Weather Service here only keep record of lightning activity

    and
    > > can not differentiate between whether it was cloud-to-cloud activity or
    > > cloud-to-ground activity. Damage via lightning (we have discussed this
    > > with various lightning experts in the US) can only take place when it is

    a
    > > cloud-to-ground strike and thus we are back to square 1.

    >
    > Yep, you'd be much better off attempting to rub the insurance
    > company's nose in the fact that the only real evidence of what killed
    > the PC is what other electronic appliances also died at the same time.
    >
    >
    > > "Oldus Fartus" <> wrote in message
    > > news:bnbugk$12lm$...
    > > > In news:bnbfqr$mhe$,
    > > > ForensicOke <> wrote these words:
    > > >
    > > > | BlankIs there anybody out there that can provide me with some advice
    > > > | on the testing of computer equipment for traces of lightning damage/
    > > > | power surge damage? We test computers for the insurance industry

    when
    > > > | a claimant makes a claim regarding "lightning damage/ power surge
    > > > | damage" to computers and computer peripherals.
    > > >
    > > > In about fifteen years of computer servicing I have only come across a
    > > > handfull of lightning damaged computers, and of those several have
    > > > exhibited very clear signs of damage. One was quite spectacular with

    a
    > > > hole burned into an internal modem where several components just
    > > > disintegrated, and another showed signs of damage around the serial

    port
    > > > on the motherboard. In a couple of other cases I have been able to

    see
    > > > no clear signs of any damage, and could only rely on anecdotal

    evidence.
    > > > (For example, the day after a severe thunderstorm someone brings in a
    > > > computer which stopped working during the storm.) Thorough

    examination
    > > > of the motherboard may show signs of damage to some of the circuit on
    > > > the underside of the board, or there may be no damage evident at all.
    > > > I have only once been asked to give an insurance statement regarding
    > > > lightning damage to an external modem, and was quite happy to do so,

    as
    > > > my own external modem had been damaged the same day during a storm.
    > > > (Incidentally, that was the only time I have had such damage to my own
    > > > computers.)
    > > >
    > > > Power surges may cause similar damage, but more often than not I have
    > > > found any damage to be in the power supply - I can not recall any case
    > > > where there has been motherboard damage which could be attributed to a
    > > > power surge.
    > > >
    > > > Obviously my experiences may be different to others. I live in an

    area
    > > > which is not particularly lightning prone, and which has a relatively
    > > > stable power supply, so I can only suggest you rely on gut feeling in
    > > > the absence of any hard evidence of damage.
    > > >
    > > > --
    > > > Cheers
    > > > Oldus Fartus
    > > >
    > > >
    > > >

    > >
    > >

    >
    >
     
    ForensicOke, Oct 30, 2003
    #5
  6. ForensicOke

    ForensicOke Guest

    I just want to thank you guys for all the info and response to my question.
    We are working through all the info we got from you and really appreciate
    it!

    Thanks again!

    "Rod Speed" <> wrote in message
    news:bnehhu$10kg4q$-berlin.de...
    >
    > Phil Allison <> wrote in message
    > news:3f9a2e27$0$28123$...
    > > ForensicOke <>

    >
    > >> Furthermore, I would like to know if there is a way to differentiate
    > >> between a power surge not caused by lightning and a spike caused
    > >> by lightning by testing the components on the motherboard?

    >
    > > IMO "power surge" = lightning induced voltage
    > > spike on the AC suppy - including the earth wire.

    >
    > Not always. I have seen one situation where the power suppliers
    > automatic tap changer failed. That normally adjusts the voltage
    > the customers see as the load changes, by changing the tap
    > as the name suggests. When it failed, the voltage supplied to
    > to the town increased gradually thru the evening as the load
    > dropped off and ended up frying quite a bit of stuff town wide.
    >
    > A DEC PDP9 minicomputer, in a big metal wardrobe sized
    > set of cabinets has an entire column of fans vertically up the
    > edge of the door that contains all the plug in discrete transistor
    > modules. As the mains voltage gradually increased thru the
    > evening, eventually all those fans started to emit a column of
    > smoke and flames. Fortunately someone was in the computer
    > room that evening and just shut the system down before the
    > whole thing went up in flames.
    >
    > The other not that uncommon situation where you can get
    > power surges that dont have anything to do with lightning
    > is when some fool knocks down a power pole, usually with
    > a car or truck, and the 11KV or 33KV distribution lines at
    > the top of the poles ends up across the 240/415 lines lower
    > down the poles for a short time until the system shuts it down.
    >
    > I've also seen a situation where a storm with no lightning,
    > just high winds, dropped a branch across the power lines
    > down the street, with a wet branch forming a conductor
    > between the 11KV line and the 240V line lower down.
    > Caused quite a bit of damage to appliances in the street.
    >
    > You can also get failure of the distribution
    > transformers the supply authority uses too.
    >
    > > Lightning surge = lightning induced voltage spike
    > > on any other thing ( eg phone cables, antennae ... )

    >
    > And the power lines down the street.
    >
    >
     
    ForensicOke, Oct 30, 2003
    #6
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