Favorite Call

[fatesplaything.livejournal.com]

I think I've just had my call of the week, my notes for this case read as follows:

No Sync - site struck by lightning

PowerCycling Resolved Issue

(x-posted to fatesplaything and techsupport)

Comments

[anivair.livejournal.com]

the great power cycle fixes all.

[torkell]

I'm suprised that powercycling solved it - I'd have expected to find the (possibly smoking) remains of a modem.

[jecook]

Seconded. WHile I've never seen the aftereffects of a direct lightning strike on common electronics, I have seen the effect of two phase on a machine that's supposed to be powered by single phase (and it ain't pretty).

I would definately replace all the surge protectors after that...

[torkell]

I've not seen the effects of a direct lightning strike, but I've seen close. A friend got his computer fried through a combination of nearby strike and absence of surge protectors, and the result of that was dead mboard/cpu/ram/psu, and probably more as well (it powered up, but then went haywire before it got as far as posting). Another tale I heard was from university, where a stirke to ground behind a building killed the fire alarm control panel on the other side of that wall, at about 3am. The failure mode for that was apparently to set all the alarms off, continuously, until someone cut both the main and battery power for the system.

I'm curious as to how a single phase machine got fed two phases. In the UK supplies are 3x240v, and stuff generally either wants one leg (most stuff) or all three (industrial kit), so about the only way you'd get two phases wired together would be if the local transformer rebelled, or you had a suicidal electrician. Then again, given the changes they're making to the wiring colours this could be quite likely.

[jecook]

The client who had this happen was having some electrical work done on their building, and the electrician (whom we named sparky during the post-mortum analysis of the machines) wired up that circuit incorrectly, putting two hot wires on the circuit instead of the "usual" hot/neutral combination.

In the US, residental electricity is supplied as 2x110v. Stuff here typically wants one phase at 110v, or two phase at 220 volt.

Amazingly enough, the machines survived, needing only new power supplies (which had exploded and caught fire).

[torkell]

Ouch.

One trick I managed when putting a friends computer together was to set the power supply to 110v (it actually came like that, which is a bit suprising - I'd have thought setting it to 240v would be safer). Unsuprisingly, the computer refused to boot. Suprisingly, the magic smoke did not escape, and when I spotted the mistake and set it to 240v it worked perfectly.

I don't know if the 110v side works anymore, but there was probably a saftey trip or similar. FWIW, it's an Antec.

[jecook]

Wow.

Unfortunately, that was one thing I never learned during my training.

After looking at schematics of power supplies with manual voltages switches, I think it involves routing the rectified DC power to an additional voltage stepdown circuit.

I could be waay off, though. My skill at reading schematics has not ben pressed into service for quite a while...

[torkell]

I think it's a sign of having spent too much time fixing computer problems (both my own and those of others) that my first set of questions includes power, as well as cables and the magical "what have you done to it?". Still haven't fully fixed my desktop, which appears to be having an ongoing disagreement between the IDE card, the VIA chipset, and the sound card, which results in it 'stuttering' every so often. I'm sure it's developed a personality, and that it's not a friendly one.

[coyoteden.livejournal.com]

Sometimes all the surge protectors in the world won't help.

I did one job where a lighening strike near the house blew out a couple of switch ports and NICs, apparently by inducing current straight through the concrete foundation.

Reminds me of the time when I was in the basement of my parent's house during a bad storm and was knocked right off my feet by the same!

[jecook]

Wow. induced current through the ground line? large amounts of ouchies.

a "quality" surge protector will claim to damp that, but that's _really_ tough to do...

[coyoteden.livejournal.com]

Not through the electrical ground, through the actual ground. In this case, induced into the cat-5 cables run across the concrete floor.

[jecook]

Oh, wow. Glad I was not there...