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lightning strike partially disables pc; next?

$tinkle

Expert on blowing
Feb 12, 2003
14,591
5
[fixing old person's computer thread]

amd chipset; can't figure out if lightning fried the on-board ethernet/nic & ability to read DVD drive, or if the mobo crapped out (it did kill the external qwest router/modem). HDD & remainder of OS functionality still intact, as are all other peripherals (printer, usb drives, keyboard, mouse).

tonight going to take over my own DVD & ribbon cable to narrow down problem. if it's the drive, so what -- who reads DVDs any more? especially elderly users who just need inet/email.

only sticking point is when they need to install a non-windows driver, like for the belkin usb wireless nic. would have same issue if i got a nic card for the only available slot.

questions:

1: how can you absolutely tell if the mobo's junked w/o serious diagnostic tools?
2: what's the best route to finding & cannibalizing another similar machine to swap parts? 2b: is it better to just newegg a new pc? saving $50, but spending 10hrs seems silly.
 

Silver

find me a tampon
Jul 20, 2002
10,846
0
Orange County, CA
Diagnosing a bad motherboard is a motherfvcker. The only way to do it is to start taking out cards and seeing what happens.

You're getting through POST and into the OS, so I'd guess it's not the motherboard (assuming its able to run for a couple of hours without a blue screen). Open it up and check all the cables. The DVD one might just be loose. You have a PCI nic you can try?
 

$tinkle

Expert on blowing
Feb 12, 2003
14,591
5
i thought i had one laying around, but no. that was going to be my sol'n if i did & not bother w/ any further madness.

you think the mobo is now unstable since the strike, and blue screens are in the user's future? it's running vista pro, which i've found to be stable
 

jonKranked

Press Button, Receive Stupid
Nov 10, 2005
61,068
7,990
media blackout
how long has it been? a few years ago i thought my PC got zapped through a surge protector... shat bricks. unplugged it, let it sit overnight, was fine in the morning. talked to some hardware nerds and basically in certain circumstances (like the one i experienced), the surge can leave a residual charge on the board that will dissipate with time. seemed weird, but my pc worked so w/e
 

Silver

find me a tampon
Jul 20, 2002
10,846
0
Orange County, CA
i thought i had one laying around, but no. that was going to be my sol'n if i did & not bother w/ any further madness.

you think the mobo is now unstable since the strike, and blue screens are in the user's future? it's running vista pro, which i've found to be stable
The bad ones I've had (2 in the last 15 years) just demonstrated notable instability. The only way to tell is to use it. Like I said, a bad MB is a bitch.

I hear ya about the dust. Sometimes you need a respirator when you open up an old case.

Parents, or aunt/uncle? :D
 
2b

Not worth fugnaround

how long has it been? a few years ago i thought my PC got zapped through a surge protector... shat bricks. unplugged it, let it sit overnight, was fine in the morning. talked to some hardware nerds and basically in certain circumstances (like the one i experienced), the surge can leave a residual charge on the board that will dissipate with time. seemed weird, but my pc worked so w/e
It would be interesting to see that substantiated, but I doubt it.
 

Pesqueeb

bicycle in airplane hangar
Feb 2, 2007
30,283
5,689
Riding the baggage carousel.
2b

Not worth fugnaround



It would be interesting to see that substantiated, but I doubt it.
Not a hard core computer nerd myself, but on our airplanes there are several fancy electronic gizmos that you really shouldn't touch until you've had power off for at least 15 minutes. That doesn't count things like Strobes and Igniters that have some fairly large capacitors that can kill you up to several hours after shutdown if your not careful, but I assume most computers don't have those.
 

binary visions

The voice of reason
Jun 13, 2002
21,700
506
NC
You can look for damaged electrical components on the motherboard, especially bulging, broken or leaking capcitors. The most common instabilities in motherboards come from damaged capacitors that behave differently depending on heat/current and what actual components they're part of.

There's no great way to test motherboards, though, since there's no centralized way to run a test of all of the components on it.

eBay is often your best bet for cheap replacement parts. I actually have some AMD parts at home but it may not be cost effective to ship them internationally. When you factor labor in, though, you can get awfully cheap new/refurb parts or entire machines. Dell's scratch-and-dent inventory is often very good and very cheap.
 

binary visions

The voice of reason
Jun 13, 2002
21,700
506
NC
Also, I call B.S. on anything in a computer retaining a charge for more than a couple minutes. Certainly, there is nothing on the motherboard that has a charge for more than a couple seconds after power-off (the motherboard is grounded through the power supply, so charge drains off very quickly) and even the power supply, which has some sizable caps in it (when I say sizable, I mean sizable for a computer), isn't going to retain much power. I bet it's drained off in <5 minutes. Less if it's plugged in, since it's grounded.
 

jonKranked

Press Button, Receive Stupid
Nov 10, 2005
61,068
7,990
media blackout
It would be interesting to see that substantiated, but I doubt it.
Also, I call B.S. on anything in a computer retaining a charge for more than a couple minutes. Certainly, there is nothing on the motherboard that has a charge for more than a couple seconds after power-off (the motherboard is grounded through the power supply, so charge drains off very quickly) and even the power supply, which has some sizable caps in it (when I say sizable, I mean sizable for a computer), isn't going to retain much power. I bet it's drained off in <5 minutes. Less if it's plugged in, since it's grounded.
then please provide me a better explanation as why my computer didn't work for 4-5 hours after the surge protector tripped during a lightning storm, and my machine immediately shut down. it was powering on after a few minutes, but the bios didn't load, there was just a bunch of random bullsh*t on the screen (not even normal dos like characters, just random pixels), and then miraculously it worked the next morning. I'm all ears.
 

$tinkle

Expert on blowing
Feb 12, 2003
14,591
5
then please provide me a better explanation as why my computer didn't work for 4-5 hours after the surge protector tripped during a lightning storm, and my machine immediately shut down. it was powering on after a few minutes, but the bios didn't load, there was just a bunch of random bullsh*t on the screen (not even normal dos like characters, just random pixels), and then miraculously it worked the next morning. I'm all ears.
did you have one of those built in UPS in the SP?
 

silent bob

Chimp
Jul 31, 2011
3
0
Also, I call B.S. on anything in a computer retaining a charge for more than a couple minutes. Certainly, there is nothing on the motherboard that has a charge for more than a couple seconds after power-off (the motherboard is grounded through the power supply, so charge drains off very quickly) and even the power supply, which has some sizable caps in it (when I say sizable, I mean sizable for a computer), isn't going to retain much power. I bet it's drained off in <5 minutes. Less if it's plugged in, since it's grounded.
Agreed , even power supplies will only hold a charge for UPTO 5 minutes and not even that in most cases .
The first thing to go in a lightning strike is the NIC , either onboard or seperate card , then the rest of the crap inside , usb,vid cards , hard drives , that kind of stuff .
If you got the cash , go to newegg
 
then please provide me a better explanation as why my computer didn't work for 4-5 hours after the surge protector tripped during a lightning storm, and my machine immediately shut down. it was powering on after a few minutes, but the bios didn't load, there was just a bunch of random bullsh*t on the screen (not even normal dos like characters, just random pixels), and then miraculously it worked the next morning. I'm all ears.
Low line voltage, although unlikely, would be a better candidate than stored charge anywhere on your motherboard. None of the supply voltages exceed 12 volts nominal and most are way under that. Apply more, and semiconductors fail. Permanently.

There are higher voltages in the power supply of a desktop, order 300 VDC; even that bleeds down in minutes and the same principles apply regarding overvoltage.
 

valve bouncer

Master Dildoist
Feb 11, 2002
7,791
36
Japan
then please provide me a better explanation as why my computer didn't work for 4-5 hours after the surge protector tripped during a lightning storm, and my machine immediately shut down. it was powering on after a few minutes, but the bios didn't load, there was just a bunch of random bullsh*t on the screen (not even normal dos like characters, just random pixels), and then miraculously it worked the next morning. I'm all ears.
My laptop wouldn't work after a blackout one time. Nothing, no lights, sfa. Googled it and somewhere came across the advice to "take the battery out and let it sit for a bit" so did that and whaddyaknow, it then worked fine. So I'm with you JK, if it works it works. Electrickery is a strange beast.
 

binary visions

The voice of reason
Jun 13, 2002
21,700
506
NC
then please provide me a better explanation as why my computer didn't work for 4-5 hours after the surge protector tripped during a lightning storm, and my machine immediately shut down. it was powering on after a few minutes, but the bios didn't load, there was just a bunch of random bullsh*t on the screen (not even normal dos like characters, just random pixels), and then miraculously it worked the next morning. I'm all ears.
"A strange thing occurred. Broken laws of physics must be the answer."


There are a fair number of components on computers that are sensitive to heat - capacitors can be somewhat heat sensitive, thermistors are directly heat sensitive, and all of those things could be affected by a lightning strike. Heck, it could have destroyed a capacitor or two and you might never know it - I've seen PCs operate fine for a long time with leaking caps, and the symptoms are often erratic.

I'm not saying I have a great answer, considering I wasn't there to do testing etc. I'm not even saying it's completely impossible that some kind of residual charge was the cause. It's just very unlikely, since there are no electrical components on a motherboard capable of retaining a charge for any length of time.