Dial up modem problem

[Matty]

Hi All

My friends PC is failing to connect to the internet through her dial up
modem. It dials but then all we hear is the repetitive beeps as for an
engaged tone (beep beep beep beep etc etc).

I have tried a new dial up connection, tried to connect through the windows
connection set-up and through hyper terminal.. all with the same result. I
have uninstalled and reinstalled the modem, loading the drivers from the cd,
even tried a different slot, all with the same result.

A phone works on the same wall port with no problem. I have swapped leads
from pc to wall port with same result.

I am assuming its the modem unserviceable and will swap it later today, but
am looking for some advice. The fault appeared after a lightning storm
though no other faults have appeared. I do wonder if this is purely
coincidence!!

For info the system is based on a Duron 1.1Ghz, running Windows XP Home. The
modem is a Creative Blaster V92 DI5732 (which I believe is the softmodem).

Many thanks in advance

Matty

 

[kony]

Hi All

My friends PC is failing to connect to the internet through her dial up
modem. It dials but then all we hear is the repetitive beeps as for an
engaged tone (beep beep beep beep etc etc).

I have tried a new dial up connection, tried to connect through the windows
connection set-up and through hyper terminal.. all with the same result. I
have uninstalled and reinstalled the modem, loading the drivers from the cd,
even tried a different slot, all with the same result.

A phone works on the same wall port with no problem. I have swapped leads
from pc to wall port with same result.

I am assuming its the modem unserviceable and will swap it later today, but
am looking for some advice. The fault appeared after a lightning storm
though no other faults have appeared. I do wonder if this is purely
coincidence!!

For info the system is based on a Duron 1.1Ghz, running Windows XP Home. The
modem is a Creative Blaster V92 DI5732 (which I believe is the softmodem).

Many thanks in advance

Matty

Yep it's a soft/winmodem. Since this is occuring right after a
lightning storm, and further "assuming" that it worked properly before
the storm, I'd call it dead and buy a new one.

Nothing against Creative but their modems are overpriced for what they
are, you can get an equivalent controllerless winmodem for $10 these
days, if that's the price-range you're wanting, though even at that
minimum price some are better than others. The 2nd link might be
about the best value for ~$10, has a Conexant chipset with greater
funcitonality than most ~$10 modems, and it has Linux drivers too
(probably not included with the modem but found here:
http://www.linuxant.com/drivers/ )


http://www.newegg.com/app/viewproduct.asp?description=25-119-102


Dave

 

[Graham W]

Hi All

My friends PC is failing to connect to the internet through her dial up
modem. It dials but then all we hear is the repetitive beeps as for an
engaged tone (beep beep beep beep etc etc).

I have tried a new dial up connection, tried to connect through the windows
connection set-up and through hyper terminal.. all with the same result. I
have uninstalled and reinstalled the modem, loading the drivers from the cd,
even tried a different slot, all with the same result.

A phone works on the same wall port with no problem. I have swapped leads
from pc to wall port with same result.

Use the phone to dial the modem number and assess if you can hear
the ISP's modem screaming data at you. If you continue to hear beeps
you can safely assume it's engaged.

 

[Alceryes]

My friends PC is failing to connect to the internet through her dial up

modem. It dials but then all we hear is the repetitive beeps as for an
engaged tone (beep beep beep beep etc etc).

This describes exactely what happens when you try to use *70 in the phone
number to disable call waiting, when you don't have call waiting on that
line.

 

[Battleax]

Hi All

My friends PC is failing to connect to the internet through her dial up
modem. It dials but then all we hear is the repetitive beeps as for an
engaged tone (beep beep beep beep etc etc).

I have tried a new dial up connection, tried to connect through the windows
connection set-up and through hyper terminal.. all with the same result. I
have uninstalled and reinstalled the modem, loading the drivers from the cd,
even tried a different slot, all with the same result.

A phone works on the same wall port with no problem. I have swapped leads
from pc to wall port with same result.

I am assuming its the modem unserviceable and will swap it later today, but
am looking for some advice. The fault appeared after a lightning storm
though no other faults have appeared. I do wonder if this is purely
coincidence!!

For info the system is based on a Duron 1.1Ghz, running Windows XP Home. The
modem is a Creative Blaster V92 DI5732 (which I believe is the softmodem).

Many thanks in advance

Matty

Even a slight power surge in the phone line can render a modem useless.
Phones are more robust and shrug it off but between me and friends I've seen
three modems die this way, right after a lightning storm.
B

 

[CBFalconer]

This describes exactely what happens when you try to use *70 in
the phone number to disable call waiting, when you don't have
call waiting on that line.

Around here the symptom of that is a voice message saying "you
don't have that service". I ran into this recently when we
removed the feature. A very stupid action by the telco, since
without the service there will be no interruption anyhow.

 

[Matty]

Use the phone to dial the modem number and assess if you can hear
the ISP's modem screaming data at you. If you continue to hear beeps
you can safely assume it's engaged.

I have tried this..and they all work fine. Also I have dialled the ISP
number and get the screaming as mentioned.
From this I assume its the modem u/s. I will swap it later today and get
back to you all.
Many thanks to all who replied. Hopefully I will sort it later.

Matty

 

[Nigel Kendrick]

Sorry, but...

Modems are rarely damaged by phone line surges.

Not so - modems are **often** damaged...etc

Modems even have galvanic isolation that separates modem for phone line.

They'll either have a fusible transformer that 'sacrifices' itself in the
event of a surge in order to protect the PC, or an optical coupling that
sort of does the same thing.

But modems have a

direct connection to one AC mains electric wire.

Nope - full isolation via the power adaptor (so-called 'double insulated' if
in a plastic case). If internal to a PC, the only power connections with be
to the DC power bus. There should be no circuit path between the AC input
and the low-voltage DC side unless an auto-transformer has been used -
highly unlikely.

Surges must first form a complete electrical circuit. >Current passes

completely through everything in that circuit. Only then does one part of
that circuit fail - become surge damaged.

In the event of a lightning strike or phone line surge caused by a distant
strike, 'circuits' will include air paths due to the high potential
difference ('voltage' if you must) of the surge. Simply having the kit on a
surface that has a low-to-high resistance path to earth (ie a table with
metals legs or a nearby metal desk lamp or grounded PC case) may form a
circuit. Also remember that nearby/direct lighting strikes can contain
high-frequency components that will drive voltage through insulation.

Telephone lines already have effective surge protector.

Not for a major surge.

Phones that do not connect to AC mains are typically
not damaged by such surges.

Sorry, not so. HF components and EMP-induced currents can fry kit in the
vicinity even if there's no direct connection to anything. - a mobile phone
left in the middle of a desk can be fried by a nearby lightning strike.

NK

 

[w_tom]

As soon as a read about 'fusible' components that protect other
components, then I know the poster does not have electrical training.
Yets put up a few simple numbers. Destructive transients occur in
microseconds. Even the fastest blowing fuse takes tens of
milliseconds. This is a classic myth no based upon technical
knowledge:

either have a fusible transformer that 'sacrifices' itself in the
event of a surge in order to protect the PC, or an optical coupling
that sort of does the same thing.

There is no sacrifical component to save electronics - except where
urban myth replaces electrical knowledge. Modems are rarely damaged
by phone line surges. In the UK, this is different because in North
America, all incoming phone lines have a 'whole house' protector
installed free by the telco. For some reason, before the transistor
became a household standard, BT stopped installing premise interface
protection. UK modems suffer surges both from AC electric and from
phone line because neither utility has 'whole house' protectors.


Furthermore the concept of breakdown voltage is totally unknow to
the poster. Even optocouplers have breakdown voltages typically
starting at 2000 volts. But computer power supplies also have
internal protection that will withstand common mode transients of
about 2000 volts - as has been industry standard for 30 years. IOW
appliances already have effective protection that assumes the 'whole
house' protector will earth the direct strike before entering the
building. Internal protection sufficient to make those indirect
lightning strikes nothing but urban myth. Why then would a transient
cause hardware damage? Because of something called breakdown voltage
and because a 'whole house' protector did not shunt before that surge
could enter a building.

Effective protection shunts a surge to earth ground before the surge
can enter a building. It is why phone line surges in North America
are usually not the reason for modem damage. Every incoming utility
must have some sort of 'less than 3 meter' connection to central earth
ground - either by hardwire or by 'whole house' protector. Once
inside the building - especially on AC electric - then the surge has a
destructive path to earth ground via appliances - ie that modem. Most
modems in North America suffer damage from surges on AC mains. Surge
damage is easier in UK where even the phone line has no 'whole house'
protector.

Surges do not enter a building, damage some component, then stop.
They first seek a circuit to earth ground. Only then does something
in that circuit fail. The only effective protection is earthing a
surge before it can enter the building - as Franklin demonstrated in
1752 - as research papers from Westinghouse and GE demonstrated in the
1930s - as is standard everywhere that surge damage is not an option -
as is standard when the home owner wants effective protetion at costs
tens of times less per protected appliance.

That claim of EMP induced surges is only another urban myth that
falls flat on its face when the myth purveryor cannot provide numbers
to support that claim. Appliances have such good internal protection
that only the direct strike causes damage. Damage traceable to human
failure because human did not install effective 'whole house'
protectors for a 'less than 3 meter' connection to central earth
ground.

 

[Nigel Kendrick]

As soon as a read about 'fusible' components that protect other

components, then I know the poster does not have electrical training.

Actually, I'm an electronics engineer by training, including 4 years on an
electronics engineering apprenticeship and a total of 6 years as an
electronics design engineer for visual systems for flight simulators.
of a surge in order to protect the PC,

Instead of 'transformer', I should have written 'isolation circuit'. The
transformer isolation circuit in a modem includes components to damp mild
surges - MOVs, gas arrestors, zener / avalanche diodes etc. These will fail
in the presence of *massive* surges but will often damp down potentially
damaging (to the PC) surges to safer levels.

There is no sacrifical component to save electronics - except where

urban myth replaces electrical knowledge.

Obviously not seen a crowbar circuit then--but that's off topic

In the UK, this is different

Freeserve is a UK ISP and so it would be safe to assume that all discussion
points in this newsgroup should be based on UK conditions

Furthermore the concept of breakdown voltage is totally unknow to
the poster.
Even optocouplers have breakdown voltages typically starting at 2000

volts.

Er, no it isn't but I wasn't specifically referring to breakdown or
flashover between the input and output of the opto isolator - a surge on the
input circuit will damage the opto isolator even if the applied emf is
insufficient to flash over to the output side so, in effect, the opto
isolator has sacrificed itself in order to protect other equipment.

Surge damage is easier in UK where even the phone line has no 'whole

house' protector.

Exactly

That claim of EMP induced surges is only another urban myth that
falls flat on its face when the myth purveryor cannot provide numbers
to support that claim. Appliances have such good internal protection
that only the direct strike causes damage.

You want numbers - OK, read the following article which has data related to
electromagnetic pulse damage caused by lightning.

www.ees-group.co.uk/downloads/Secondary%20Effects.pdf

NK

 

[w_tom]

This discussion is cross posted to numerous newsgroups - not
just a UK newsgroup. Concept of breakdown voltages still
apply on both sides of the pond. For example isolation
transformer in modem's DAA circuit may provide 2000 volts of
galvanic isolation. However destructive common mode surges
are current sources. That current will increase voltage, as
necessary, to turn that transformer or optocoupler into a
conductor. Either they provide isolation without damage, or
they do not and become damaged as surge passes through.
Through seeking what? Earth ground.

Protector components do not sacrifice themselves to protect
electronics. Either destructive current flows through them or
no current flows - no damage. But again, destructive common
mode surges cannot be stopped, blocked, filtered, or
absorbed. As in a flood, the dam will not stop a flood. A
dike will divert the flood, but only if the flood is shunted
downstream. Galvanic isolation works like a dike. Only
effective IF the surge has some other, non-destructive path
downstream - to earth ground. That is what the 'whole house'
protector does; shunt the surge downstream to earth.

Appliances already have galvanic isolation. But again, that
internal protection will only be effective IF the surge is
earthed before entering a building. Appliances already have
'dikes' that will be overwhelmed if the surge is not earthed
before entering the building. Just as dikes work for the
town. If flood is not provided a downstream path, then 'dike'
is acting like a dam - and is overwhelmed.

There are no sacrificial components in an effective
protection system. Even a thyristor based crowbar circuit is
properly sized to shunt without damage. A common mode
transient either does nothing to the optocoupler OR creates a
plasma path through that optocoupler. A direct lightning
strike is earthed without damage to transistors or the
protector. Protection is not difficult and performed so often
that protector damage is not an option. No sacrificial
components are found or used in an effective protection
system.

www.ees-group.co.uk/downloads/Secondary%20Effects.pdf
An interesting discussion, but where does this apply to
anything posted here? What numbers apply to this discussion?

We know how to protect everything from direct lightning
strikes without damage even to the surge protectors. Moreso,
the protection is so inexpensive. However plug-in protectors
ARE expensive and not effective protection - which is why
they don't even claim to provide such protection.

Described in the previous post is how effective protection
from direct lightning strikes is implemented - complete with
products and where they can be purchased. Even the
www.ees-group.co.uk article does not dispute what was posted.
Bottom line is this: a surge protector is only as effective as
its earth ground.

 

[Richard Unsworth]

All I know is that many people I have spoken to while answering technical
support lines have suffered blown modems due to a nearby lightning storm.
eg. 1. It worked and connected 2. There was thunder and lightning nearby 3.
It says 'No dial tone'.
And this happened to my pc - I heard just one spectacular bang the April
before last - I was about a mile and a half from home. The next day I
switched on the pc - dead. Nothing. Having left my diagnostic brain at work,
it didn't dawn on me until a local child said 'Have you seen where the
lightning blew the paving stone into the road?' This was sixty yards down my
street. Result? Modem, motherboard, memory, graphics card, sound card -
every component attached directly to the motherboard was dead. w_tom can say
all he likes about electrical theory, but experience has shown me that
lightning surges down the phone line blow modems up! After my own
experience, I like to tell callers that the modem has acted as a fuse, and
saved the rest of their P.C. - they seem to find this reassuring!

 

[ste00]

every pc tech who knows ne thing about pc's will tell you surges down phone
lines kill modems and sometimes entire pc's, so the dumb f@@@@ who keep
coming on here and saying that they don't need to re-train.

 

[w_tom]

This is deception:

I like to tell callers that the modem has acted as a fuse,
and saved the rest of their P.C.

Lightning has traveled many miles through non-conductive
air. Is a silly little 'fuse' going to stop what miles of air
did not? Of course not. But basic technology also says a
fuse (response time > 10 milliseconds) cannot possibly protect
from a surge (typically < 100 microseconds). No fuse is
installed to provide such protection - as demonstrated twice
over.

First, surge passed through modem's off-hook relay circuit
and other components including motherboard ground plane. Only
then does something fail; typically a modem off-hook relay.
Typical reason for so many computer peripherals damaged -
surge entered on AC electric and exited to earth ground via
other paths. No damage can occur without both incoming and
outgoing path. One traditional path that causes "No Dialtone
Detected" message is incoming on AC electric and outgoing on
phone line to earth ground. Damage that has often been
demonstrated by replacing off-hook PNP transistor; making
modem work again.

Surge damage is traceable to wires that entered building
without a connection to central earth ground. Modem never
acts like a fuse nor protected anything. That surge, as
taught in primary school science, first must have passed
through everything in a complete electric circuit. Many
forget primary school science when rationalizing about surge
damage. Many say the surge entered on phone line, damaged
modem and stopped - a direct violation of primary school
science. It is that simple. Modem was damaged because surge
first took a complete circuit path through that computer - and
only then damaged something.

 

[Richard Freeman]

This is deception:
Lightning has traveled many miles through non-conductive
air. Is a silly little 'fuse' going to stop what miles of air
did not? Of course not. But basic technology also says a
fuse (response time > 10 milliseconds) cannot possibly protect
from a surge (typically < 100 microseconds). No fuse is
installed to provide such protection - as demonstrated twice
over.

First, surge passed through modem's off-hook relay circuit

You are starting to grasp the concept then .

and other components including motherboard ground plane.

well since we are being pedantic here try "heading for the Ground plane"

Only
then does something fail; typically a modem off-hook relay.

built in surge arrestors, Input and Output op-amps, Modem processor, Modem
PSU etc etc etc

Typical reason for so many computer peripherals damaged -
surge entered on AC electric and exited to earth ground via
other paths.

Damn just when I thought w_tom had grasped the concept. Once again w_tom
goes on with his fantasy that Lightning comes in via AC mains and exits via
the phone Line.

Lets see now applying a little bit of Basic Physics and electrical Theory we
have two Lines:

Phone Line:
No earth on either leg of the cable in fact a very high impedance path to
earth via the phone line maybe several kms away.
thin relatively high impedance wire with a DC resistance alone running to
tens of Ohms (which is why exchange damage is less common - but still
occours)

AC Mains:
typically runs multiple earthed Neutral that is multiple Earth points (in my
street about every 25 metres or so)
Relativily thick low impedance often multi strand cabling a fraction of an
ohm in impedance and with even the Active to Neutral path (via the
Transformer) giving a nice low impedance path to earth.

hmmmm no prizes for guessing which is the better path to earth here folks !

No damage can occur without both incoming and
outgoing path.

yep !

One traditional path that causes "No Dialtone
Detected" message is incoming on AC electric and outgoing on
phone line to earth ground.

BS! incoming Lightning coming in via the phone line blowing the living *^&t
out of the modem on the way through and exiting the far superior earth on
the AC mains

Damage that has often been
demonstrated by replacing off-hook PNP transistor; making
modem work again.

In the event of a distant strike maybe if you are lucky (but lets face it
who fixes modems nowadays ?)
in the event of a near or direct strike ... Forget it your modem is toast.

Surge damage is traceable to wires that entered building
without a connection to central earth ground. Modem never
acts like a fuse nor protected anything. That surge, as
taught in primary school science, first must have passed
through everything in a complete electric circuit. Many
forget primary school science when rationalizing about surge
damage. Many say the surge entered on phone line, damaged
modem and stopped -

Well almost more like Lightning entered modem via phone line and found nice
alternative paths to earth via AC mains - also via your PC motherboard if
you have an internal modem. But to all intents and purposes since it was
safely shunted to (mains) earth at this point and if it did no further
damage. it effectively dissapeared from the users view at this point.

a direct violation of primary school
science. It is that simple. Modem was damaged because surge
first took a complete circuit path through that computer - and
only then damaged something.

well if you are being a pedant it took a complete circuit path through that
computer and fried it en route.


Yep thats classified as a near strike

I dunno why, he has a little trouble grasping basic electrical theory.

Yep that right and anyone else in the Comms/Data Comms industry would tell
you exactly the same thing.
two useful tips:
1) unplug the phone line from your modem/PC when not in use
2)use an external modem for preference - it is no guarantee but at least it
keeps lightning that one step further away from your PC

well while not strictly correct, I know what you mean.
Maybe for the sake of the pedants word it as : "your modem acted as a surge
arrestor and redirected the Lightning to the Mains earth"

Regards
Richard Freeman

 

[Franc Zabkar]

Damn just when I thought w_tom had grasped the concept. Once again w_tom
goes on with his fantasy that Lightning comes in via AC mains and exits via
the phone Line.

I was skeptical, too, until I saw it for myself. See this post:

http://groups.google.com/[email protected]&output=gplain


- Franc Zabkar

 

[Richard Freeman]

I was skeptical, too, until I saw it for myself. See this post:

http://groups.google.com/[email protected]
u&output=gplain

Firstly where is this earth on the Telephone line ????? - It does not exist.
some (in Australia very few) phone lines have surge arrestors but these are
not generally implemented as they have proven to be ineffective in the case
of near/Direct strikes.

going through your list :

Firstly, my friend's neighbour lost his electrical distribution box,
so this confirms that the strike came in on the mains.

Well Maybe and I have not said it never comes in via Mains just that if it
does it is so uncommon that I have not seen it.
Reading through the list of damage however suggests that your friend
suffered a direct strike in which case :

A) all bets are off
B) a Lightning strike that has blown the shite out of a switchboard is
barely going to flinch at blowing the shite out of a MOV
C) Equally likely and the more probable scenario is that your friends house
was hit and the Lightning followed the path to the best Earth available -
that of the MEN Mains

Failure of PCtel DAA module (plug-in type for PCChips M585LMR
motherboard). Symptom was "NO DIALTONE". Parallel telephone was
undamaged. Both phone cables were plugged into a "protected" power
board.

Plug in module connected to the phone line - still matches the scenario that
the strike came in via Phone and exited via Mains
The parallel phone most likely rode out the strike. In fact this sounds like
a module in a PC if the strike came in via the Mains and exited via the
phone line why wasnt the PSU fried ? the more likely scenario is that the
strike came in via the phone line and headed for the chassis earth on the
PC.

(2) Portable telephone base station - shorted 15V zener diode at tip
and ring inputs.

Powered phone connected to the phone line - still matches the scenario that
the strike came in via Phone and exited via Mains

(3) Television - shorted rectifier diode, blown fuse, and failures in
the +5V regulator, remote sensor, and microcontroller.

(4) Two VCRs - CPU and power supply failures.

Nasty sounds like a direct strike which also entered via the TV aerial and
headed for the earth provided via the double insulated mains - note no phone
line involved here

(5) Audio unit - CPU failure, P/S OK.

Dont know what this was but if double insulated equipment connected to the
VCR/TV then Lightning was probably still travelling in via the TV aerial and
had not dissipated completely via the VCR or TV Again no phone line
connected here

(6) Security light - faulty power controller, light dims but won't
turn off.

Sounds like a direct strike The Light being installed outdoors probably
copped a secondary strike not the full Strike - you would have found that
one of w_toms surge busters would not have saved this anyway. Also no phone
line involved here

(7) TV - blown fuse, damage to P/S

entered via the TV aerial headed for the AC mains again no phone line
involved here

Well sounds like your Lightning still mostly obeyed the laws of Physics and
entered by unearthed / poorly earthed paths and headed straight for the best
earth available that of the AC Mains. as an addendum the mains in this
instance probably rode out the strike to a certain degree but in all the
cases a path for the lightning to have entered by other than AC mains
exsists.
Lightning aint Rocket science it obeys the laws of physics - it is just with
high energy events such as lightning different laws of physics often come in
to play.
Lightning seeks a path to the best earth it can find and note here that a
single earth stake buried in the ground is more often than not hardly the
best earth available the MEN system however used for 240/415V mains
distribution however frequently offers a superior earth for Lightning
strikes

Regards
Richard Freeman

 

[Franc Zabkar]

Firstly where is this earth on the Telephone line ????? - It does not exist.

In normal circumstances the phone line ground is at the exchange.
However, in the case of a lightning strike, the nearest earth is the
ground surrounding the cable. In any case, if lightning were to hit
the ground, then why would it not dissipate itself in the general mass
of earth rather than travelling all the way into the house and onto
its local mains earth? Granted, the earth is not homogenous, so a
lower potential _could_ exist at the dwelling, but it would seem more
likely that an earth strike would not propagate too far away from the
epicentre.

some (in Australia very few) phone lines have surge arrestors but these are
not generally implemented as they have proven to be ineffective in the case
of near/Direct strikes.

going through your list :


Well Maybe and I have not said it never comes in via Mains just that if it
does it is so uncommon that I have not seen it.

I have seen it twice at the same dwelling, with similar results. On
the second occasion the datapump of an internal 33.6K ISA Rockwell
modem was damaged, but the only other problem with the entire PC was a
faulty IRQ3 signal on the ISA bus. That's two PCs, neither of which
sustained any damage other than a faulty modem DSP/DAA.

Reading through the list of damage however suggests that your friend
suffered a direct strike in which case :

A) all bets are off
B) a Lightning strike that has blown the shite out of a switchboard is
barely going to flinch at blowing the shite out of a MOV
C) Equally likely and the more probable scenario is that your friends house
was hit and the Lightning followed the path to the best Earth available -
that of the MEN Mains


Plug in module connected to the phone line - still matches the scenario that
the strike came in via Phone and exited via Mains
The parallel phone most likely rode out the strike. In fact this sounds like
a module in a PC if the strike came in via the Mains and exited via the
phone line why wasnt the PSU fried ?

Clearly the strike struck the mains at some point, so one would
intuitively expect that everything connected to the mains would have
suffered significant damage, as you say. The fact that the PSU
survived suggests that the major part of the potential difference
appeared across the DAA of the modem (???).

the more likely scenario is that the
strike came in via the phone line and headed for the chassis earth on the
PC.

So we have two strikes, one on the mains and another on the phone
line?

Powered phone connected to the phone line - still matches the scenario that
the strike came in via Phone and exited via Mains


Nasty sounds like a direct strike which also entered via the TV aerial and
headed for the earth provided via the double insulated mains - note no phone
line involved here

So now we have three strikes, one on the mains, a second on the phone
line, and a third on the aerial?

BTW, no tuners or IF stages were damaged.

(5) Audio unit - CPU failure, P/S OK.

Dont know what this was but if double insulated equipment connected to the
VCR/TV then Lightning was probably still travelling in via the TV aerial and
had not dissipated completely via the VCR or TV Again no phone line
connected here

No aerial, no phone line, just mains power.

(6) Security light - faulty power controller, light dims but won't
turn off.

Sounds like a direct strike The Light being installed outdoors probably
copped a secondary strike not the full Strike - you would have found that
one of w_toms surge busters would not have saved this anyway. Also no phone
line involved here

(7) TV - blown fuse, damage to P/S

entered via the TV aerial headed for the AC mains again no phone line
involved here

As before, no tuners or IF stages were damaged.

Well sounds like your Lightning still mostly obeyed the laws of Physics and
entered by unearthed / poorly earthed paths and headed straight for the best
earth available that of the AC Mains. as an addendum the mains in this
instance probably rode out the strike to a certain degree but in all the
cases a path for the lightning to have entered by other than AC mains
exsists.
Lightning aint Rocket science it obeys the laws of physics - it is just with
high energy events such as lightning different laws of physics often come in
to play.
Lightning seeks a path to the best earth it can find and note here that a
single earth stake buried in the ground is more often than not hardly the
best earth available the MEN system however used for 240/415V mains
distribution however frequently offers a superior earth for Lightning
strikes

I notice that the one thing that distinguishes a PC from most, if not
all the other equipment is the fact that it has an earth conductor.
What if this relatively small earth conductor allows the PC to float
to the strike potential? Wouldn't the full potential then appear
across the modem's DAA rather than the main part of the PC?

Regards
Richard Freeman

I wonder if there is some forensic or metallurgical method of
determining the direction of current flow in a lightning strike.


- Franc Zabkar

 

[Ed Medlin]

It is almost impossible to try and "scientifically" pick apart how the
energy of a direct ground strike will affect any electrical component. There
is just so much energy envolved. I live in an area in the US Midwest that
gets many violent storms that contain a large amount of ground strikes. Just
about 2 weeks ago, we had a large strike that hit the access post of our
phone lines about 30yds from my home. It blew a 3ft deep hole and completely
destroyed the phone lines to ours and three other homes. In my home, it only
disabled our phone lines and did no damage there, but I have an outside
AC/Heat pump and it came in there and completely destroyed my climate
control system. No other damage in my house. All the other homes had all
their phone outlets burned to a crisp and all phones and at least the modems
for their computers were fried. When there is that much energy, wet ground
and so many ways for the energy to enter and exit there just aren't enough
constants to analize how that energy is going to dissipate itself. There is
also no foolproof method of protecting your electronics. I have used good
quality UPSs on my electronics for some 5yrs and have been lucky since then.
Before that, I used various brands of surge protectors and was constantly
having lightning damage. I guess what I am saying is that, yes, the energy
will follow the path of least resistance, but with that much energy to
dissipate, there are lots of paths it may follow.


Ed

 

[Strontium]

Are you related to Ed LIGHT? You, both, have a very annoying habit of not
knowing how to quote.


It's helpful, in the very least of the sense.


SHEESH


SEE QUOTE, below.

-
Ed Medlin stood up at show-n-tell, in
[email protected], and said: