lightning hit PC now dead

[Bishop]

A co-worker brought me in a dell PC and said it refused to come on after a storm came through and the power failed three times, and he had left the PC ON during the storm.
When the storm was over the PC would not come on. The power supply still puts out the correct voltage.

Has anyone brought back to life a PC that died during power outages? If not it's headed for the dumpster after the cannibalization.

[Dgtech]

Re: lightning hit PC now dead

I've worked on a few with the same symptom as well as cause. Most of the power supplies I have seen in PC's are not fast enough to catch surges caused by lightning strikes. Therefore the voltage goes straight to the motherboard and kills it. I never see it go to the other devices though - HD, DVD drive, etc...

[severach]

Re: lightning hit PC now dead

Most of the power supplies I have seen in PC's are not fast enough to catch surges caused by lightning strikes.

That would be all power supplies because...

I never see it go to the other devices though - HD, DVD drive, etc...

for there to be a surge the current must go through for a complete circuit. The path is already carrying current before anything can react. The motherboard connects to enough alternate ground paths that one of them will let the surge through to ground. Those other devices have so much more impedance to ground that very little of the surge goes there.

PC power supplies cannot safely shunt away surges from lightning. That can only be done in your breaker box with a Lightning Arrestor.

[Toasty]

Re: lightning hit PC now dead

>>The power supply still puts out the correct voltage.<<
So, the power supply runs? Connected to system or not?

Is the Standby Power LED on, on mobo?
Any fans move when you try power button?
Could it have popped the MOV or thermistor in the PSU and still provide 5VSTBY?

[Bishop]

Re: lightning hit PC now dead

Tell me more about the things you think are bad, I like a challenge

[digge]

Re: lightning hit PC now dead

Ive repaired a few computers after lightning. Sometimes it was kinda obvious everything was fried though so rather scrap it and recommend buying new. But sometimes it was as easy as yanking out an internal modem and it would start right up, think its also been internal usb hubs with same symptoms.

I would suggest take it apart to bare minimum of parts and see if itll start, maybe with another PSU. If that doesnt work you decide weather or not to invest more time in repair or not.

[westom]

Re: lightning hit PC now dead

Has anyone brought back to life a PC that died during power outages? If not it's headed for the dumpster after the cannibalization.

How do you know voltages are good? Fans can spin. Lights glow. And voltages can still be completely defective.

Routine is to restore a computer from anomalies that both damage the computer and causes AC power loss (power outages never damage electronics). Step one always starts with critical numbers from some wires between the supply and motherboard.

What is voltage on the purple wire. It should read about 5 volts before the power switch is pressed. Additional facts are also in those other digits. What is that voltage to three significant digits?

What is the voltage on the green and gray wires both before and as the power switch is pressed. How long after power on does the gray wire stabilize?

And what are the voltages on any one red, orange, yellow, and the purple wire as and after the power switch is pressed? Again, numbers to three digits.

Just about everything in the machine can cause your failure. Anyone suggesting only one or two possibly defective parts is actually recommending you keep replacing parts - everything - until something works. Faster and simpler is to report those numbers. And get a reply that answers definitively - without speculation - without any doubt.

[PCBONEZ]

Re: lightning hit PC now dead

PSU isn't the only way in.

[ratdude747]

Re: lightning hit PC now dead

PSU isn't the only way in.

an accidental bypass in a phone line surge protecter caused a modem to fry and a slot in a mobo to fry once in a power surge, mom hooked the phone cords wrong and the modem was unprotected.

[westom]

Re: lightning hit PC now dead

an accidental bypass in a phone line surge protecter caused a modem to fry

All phone lines already have the best protector installed for free. Telcos have been required - longer than anyone here has existed - to install a 'whole house' protector on every subscriber interface. Where their wires meet yours.

But one must first ignore myths that promote scam protectors. First remember how electricity works. An electric current is flowing everywhere and simultaneously in a path from cloud to earth. Much later only one (or some) item in that path fails. That means damaged appliances (or modems) must have current both incoming on one path and simultaneously outgoing on another path. If both paths do not exist, then no damage. What is the incoming and outgoing path?

Well all phone lines already have an earthed 'whole house' protector. And telephone lines on the pole are protected by higher AC electric wires. Telephone lines are not the incoming path. Most all modems are damaged by surges incoming on AC mains. Incoming via two unearthed power wires. Through the modem. To earth ground via telephone line and the 'whole house' protector. First that current is everywhere, simultaneously, in that path. Much later the weakest link in that path – a modem – fails.

Modems are damaged by phone line surges when one ignores basic electricity taught in primary school science. And does not know the telco already installs an effective 'whole house' protector - for free. Those are the people most easily sold retail myths.

Surge protection always means energy dissipates outside a building. Always. If any wire is not earthed (ie AC electric wires), then a surge is inside. Destructively hunting for earth via appliances. No protector inside the house will avert that hunt. Some most easily damaged appliances are connected to the cable and telephone lines. Because those appliances are a best connection from AC electric to earth.

Why does damage happen? Human failure permits destructive energy inside the building. Once inside, the hunt for earth means appliance damage. Damage routinely averted even 100 years ago by earthing a protector where wires enter the building. Damage averted only if energy does not enter the building. Informed homeowners earth a 'whole house' protector on the AC breaker box or behind the electric meter so that modems, et al are not damaged.

Nothing inside the house will avert a destructive hunt for earth ground. Anything that attached telephone wire protector might do is already done better inside every modem.

PCBONEZ - PSU is rarely the incoming path through a computer. An adjacent plug-in protector gives surges a path around the PSU and directly into the motherboard. Adjacent protectors can bypass protection that is already inside every power supply. Retail sales prmoters do not want to discuss that. And never want to discuss the #1 fact in surge protection. Where does energy dissipate? Either harmlessly outside the building. Or it hunts destructively for earth via appliances.

Meanwhile, the faster solution to fixing a computer starts with numbers from those PSU to motherboard wires - which has nothing to do with the above paragraphs.

[Toasty]

Re: lightning hit PC now dead

All of this is neat.

Tell me more about the things you think are bad, I like a challenge

How about you start by answering my questions please.

[momaka]

Re: lightning hit PC now dead

I would suggest take it apart to bare minimum of parts and see if itll start, maybe with another PSU. If that doesnt work you decide weather or not to invest more time in repair or not.

I concur.
Start with the basics - i.e. power supply, motherboard, CPU, and memory only, all connected to a known good keyboard and monitor. Remove any other add-in cards and connectors.
No POST? Try swapping parts - first the power supply, then memory, and so on.
No POST still? Remove memory, and see if the motherboard beeps (make sure it's either connected to the system speaker or that it has an onboard buzzer).

It would also be helpful if you give us some information about the system. For example, what brand and model is the power supply? Same with the motherboard.

Lastly, check for bad caps (or caps that might be from a bad brand), especially if your co-worked had the tendency to leave the computer on all the time. Sometimes what can happen is bad caps can develop in either the PSU or on the motherboard while the computer is on but not cause a problem until the computer is shut down. Once you turn off the computer and the caps cool down, their ESR goes high enough to prevent it from working again (I had that happen with a L&C PSU - had to leave the computer boot-cycle a few times before it would run. Once running, in wouldn't crash).

[Bishop]

Re: lightning hit PC now dead

It's a 1G xp Dell. I pulled everything off the motherboard and pulled it out everything looks OK, all the caps are tight and normal, no leakage, no burn spots, no loose or burnt wires.
Changed to another PSU still the same. changed CPU from working sys and still dead.
Memory ddr looks OK.

I guess I'll save it for parts, I'll also get the original XP OS disks next week, and use them in another PC.

Thanks to all, I enjoyed the feedback, great group of guys, thanks

[ratdude747]

Re: lightning hit PC now dead

All phone lines already have the best protector installed for free. Telcos have been required - longer than anyone here has existed - to install a 'whole house' protector on every subscriber interface. Where their wires meet yours.

not at that house. i had to fix the phone wring on it last night, ironically. the old phone splices it had back then had no protection. my mom put the splitter on the wrong side of the surge protector, so my dad's computer was protected but my mom's computer/fax/phone was not. trust me, the modem was toasted... as was the pci slot (granted the board was a soyo)

[Dgtech]

Re: lightning hit PC now dead

It's a 1G xp Dell. I pulled everything off the motherboard and pulled it out everything looks OK, all the caps are tight and normal, no leakage, no burn spots, no loose or burnt wires.
Changed to another PSU still the same. changed CPU from working sys and still dead.
Memory ddr looks OK.

I guess I'll save it for parts, I'll also get the original XP OS disks next week, and use them in another PC.

Thanks to all, I enjoyed the feedback, great group of guys, thanks

My suggestion with ALL lightning strike issues is even if you have burnt components that you can swap out, there are likely to be a dozen more components that are stressed but not visably in trouble. Computers (nowadays) are made to run within such tight specs that stressed components will cause an issue somewhere down the road. Dell's are a dime a dozen and this board should not be hard at all to find and replace.

What is the motherboard model #? If you cant find this then post a picture of the board.

[PCBONEZ]

Re: lightning hit PC now dead

Where does a 900# gorilla sit? -- Anywhere it wants to.............

Surge protection ≠ Lightening protection.
- That story line is bogus.

As soon as a voltage exceeds the insulation capability of the conductor containing it you can have arcing.

Lightening from sky to ground can be up to 300,000,000 volts.
-
There is NOTHING in your house wiring or PC that is going to insulate against 300,000,000 volts.

Where does 300,000,000 volts go? -- Anywhere it wants to.............

[westom]

Re: lightning hit PC now dead

I guess I'll save it for parts, I'll also get the original XP OS disks next week, and use them in another PC.

Why would you do that? After all that work, which parts are good and which parts are bad? Accomplishment is measured by the length of those lists. With only numbers, the engineer could have expanded those lists. You probably have no idea how much information is obtained from only 1 minute of labor. Less work. Far more useful facts. Excessive work and confusion is when one swaps parts.

Lightning does not damage everything. That myth is popular among those who never fix things; only swap parts. Lightning typically damages one or a few tiny parts. Most lightning damaged computers are easily restored and do not fail years later. For example, lightning damaged modems typically only had one damaged part – a PNP transistor. But that means learning what has failed and why before replacing anything. By simply reading numbers. Most who never learn automatically assume the entire modem is toast du to some silly myth that lighting put 3,000,000,000,000 volts on that modem. Fixing means disconnecting nothing, one minute of labor - and numbers.

Post those numbers. Then learn so much about what is and is not functional inside that machine. Or just trash what is probably an easily restored machine.

"even if you have burnt components that you can swap out, there are likely to be a dozen more components that are stressed but not visably in trouble" is a classic myth. A belief popular where people only swap parts, get confused, and end up replacing lots of perfectly good parts.

[westom]

Re: lightning hit PC now dead

not at that house. i had to fix the phone wring on it last night, ironically. the old phone splices it had back then had no protection.

Which is exactly what happens when a surge, entering on AC electric, finds earth via that telephone 'installed for free' protector and telephone wires.

That protector exists on every home as required by both FCC and National Electrical code regulations. Damage to wires inside the building are mostly from surges because no 'whole house' protector is earthed where AC wires enter a building.

Surge protection is always installed to make direct lightning strikes irrelevant. But not when one is brainwashed by retail myths that promote ineffective and high profit protectors.

Many are told what to believe - and blindly recite it. The informed learn after numbers are provided. A direct lightning strike is typically 20,000 amps. So a minimally sized 'whole house' protector starts at 50,000 amps. Why? Because surge protection is always installed for lighting protection - and for trivial lesser surges.

Protection is always about where energy dissipates. Those trained from retail propaganda never learn that, will claim 'woe is me; nothing can prevent damage', and never demand the numbers. For over 100 years, direct lightning strikes were harmlessly earthed by 'whole house' protectors. Which is why lightning does not enter on phone lines. Which is why lightning damages interior wires to obtain earth ground via the 'installed for free' telco protector. Portector has been required by code long before anyone here even existed.

If damage happens, the informed homeowner fixes a human created failure. In many cases, that is difficult because so many recite retail myths. Because so few first learned the science and demand numbers. Protection is always about energy absorbed harmlessly outside the building. Damage means a human has not yet learned 100 yeasr of well proven science.

[westom]

Re: lightning hit PC now dead

There is NOTHING in your house wiring or PC that is going to insulate against 300,000,000 volts.

Learn what Franklin demonstrated in 1752. Your post contradict even Franklin's famous experiments. Lightning protection never - never - means insulating. Nothing stops lightning. Protection from direct lightning strikes means just the opposite - conducting lightning harmlessly into earth.

Scam plug-in protectors claim to insulate, block, and absorb surges. Then when it fails, the naive recommend it - and buy more. Solutions sold by responsible companies never stop (or insulate) surges. Have numbers that exceed lightning (20,000 amps). Effective surge protection means direct lightning strikes without damage. But only when one learns the 100 year old technology – and demands numbers.

Avoiding ineffective products from APC, Belkin, Monster, etc. Earth products from more responsible companies including General Electric, ABB, Square D, Siemens, Intermatic, and Leviton. An effective solution to make direct lightning strikes irrelevant is provided by Cutler-Hammer; sold in Lowes and Home Depot for less than $50. For a majority only trained in popular myths, this is the first time they are reading about ‘whole house' protection – and the always essential earthing.

It means learning science that was well understood even 100 years ago. And unlearning myths promoted by an overwhelming majority trained by retail advertisements and sound bytes. Same myths also claim lightning destroys everything inside a computer. Why have we so routinely restored so many lightning damaged electronics with but a few semiconductor replacements? Only a small minority actually knows this stuff.

[PCBONEZ]

Re: lightning hit PC now dead

What does that have to do with what gets damaged inside a PC?