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Yesterday I was trying to connect a Viewsonic Projector to my Samsung RC420 laptop... I followed this steps:

  1. I Plugged the Projector to a power source, in parallel I did the same thing with the laptop. Then I turned on the laptop, but not the Projector (this one turns a bright light when is connected to a power source).

  2. I put the VGA Cable to the Projector (this one being still turned down) and then when I was getting close to the VGA port of the Laptop... BAM! A big spark appear between the port and the cable! Immediately the whole electricity of my floor went off.

A part of the port in my laptop kind of... melted down. It seems to be where the spark started. The same thing happened to the part of the cable involved.

Now I'm using the laptop, and it seems that there is no problem in it, I haven't connect anything to the VGA port yet. And the projector is still working to, well... it turns on, and I haven't connect anything yet too.

The projector was connected to the power source by a homemade electric extension.

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Related: Why is there electricity flowing through my VGA and other ports? You likely have grounding issues, albeit with your projector rather than laptop (I say this because I read "homemade electric extension"). –  Breakthrough Oct 13 '12 at 14:43
    
This much power through the VGA port likely means there is a short in the way you hooked up the power source to the projector. Check your extension cable to make sure it is wired correctly. –  DragonLord Oct 13 '12 at 15:18
    
I'd dispose of that "homemade electric extension" (after cutting it in half) and buy a properly made one. –  RedGrittyBrick Oct 13 '12 at 18:17
    
That "homemade electric extension" probably swaps the hot and neutral. That could explain why line voltage was on the "ground" connection of the projector. You're lucky you only saw sparks and didn't get shocked. If you had turned on the PJ, it would have been a goner. –  sawdust Oct 13 '12 at 19:24

1 Answer 1

up vote 3 down vote accepted

The projector was connected to the power source by a homemade electric extension.

And, Thats why.

I put the VGA Cable to the Projector (this one being still turned down) and then when i was getting close to the VGA port of the Laptop... BAM! A big spark appear between the port and the cable!.

The outer casing of a VGA port should be a ground. It was probably at high potential. The other end was at ground potential. Apparently that caused a bolt of electricity to jump across and zap your laptop since electricity goes from low potential to high potential

Inmediately the whole electricity of my floor went off.

And, thats probably the fuse or ELCB preventing anything bad from happening.This means there's a short circuit somewhere.

As for the laptop still working, well, you got lucky, and the electricity probably got conducted to ground. It might have fried something but we can't tell without you testing it.

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> And, thats probably the fuse or ELCB preventing anything bad from happening. You mean anything else bad from happening. The source of the short is usually doomed anyway. :-( –  Synetech Oct 13 '12 at 14:54
    
Well, I've had a similar, less violent incident where both parties were still functional. I threw out the CRT that was spitting sparks out at my little mini itx box tho. NOT worth the risk. –  Journeyman Geek Oct 14 '12 at 1:12

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