thunderstorms and system failure

Yes it is true that a electrical power surge caused by a lightening strike could cause computer components to fail. As to which components will fail may be more dependent on which was most vulnerable at the time of the strike. Your modem, certainly since it was connected to a good conducter of electricity (the phone line) and since your motherboard was connected to the modem, it could certainly fail. Your hard disk drive could also fail if you were accessing it at the time of the strike. The best thing that you could do is to unplug your computer and disconnect the modem during electrical storms. This could have happened to your computer even if you were not using it at the time. Hope this helps.

My neighbor downstairs had his computer fried by lightening during a t-storm. The lightening hit the phone line and zapped his modem and system board.

Computer components are very vulnerable to this kind of thing...modems in particular. They can only tolerate power within certain ranges. ESD - static - can do damage to components, so lightning hitting and causing a massive surge is devastating. I would say this is one of the most common problems I see for runined hardware during the "storm season". My BBS (that I ran for years) lost many a modem to storms...

Your best line of defense is to buy a high quality surge protector with a port foryour phone/modem line as well. They won't always save you, but they will make your system much less vulnerable. If a storm is particularly bad, you should shut down your system and unplug it from the wall if you need to be "completely safe".

Goodluck....

Hi the problem is that the phone line has not any earth/ground reference at the home end of the line, they have surge protectors across the line but none to ground hence any charge that appears on both conductors will not cause the surge protector to work, if the surge is higher than the break down voltage of the modem protection then the surge goes straight to the supply rails of the PC hence so much damage. The problem is wide spread as we used to sell a lot of modems after an electrical storm.

Rich

Even if lightning does not directly stike your phone line, a high voltage surge pulse can be imposed on either the power line or the phone line.
These pulses can be in excess of 200 volts.

In your case, the pulse likely came in through the phoneline.
Blew up parts on the modem, and then proceeded on to the motherboard.

Note: As an old repair tech, I would junk the entire PC. All remaining parts are suspect, and could fail at any time.

Surge protectors and UPS power supplies providesome protection, but all have a limit as to how large of a pulse they will absorb.
(They also require a solid ground connection to function at all)
None of the devices will protect you from a direct lightning hit.

When ever I go away from home,or a thunderstorm is immenent, I disconnect my modem cable from the wall. If it is a strong storm, I will unplug the PC.

For a lot of details on lightning and PCs, check out www.apc.com
Yes, their primary goal is to sell you power protection, but they have a number of good resources to help you understand the scope of the problem.

Chas

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