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Old 06-27-2007, 10:32 AM   #1 (permalink)
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Default Video Card Power Feeback?

Hey everyone, nice to be here, etc., etc. You know the drill. I was wondering if any of you guys could help me on the account of my machine.

This last Thursday, we had a nasty rainstorm in the midwest, and my room (in the basement, yeah yeah, stereotypical, I know) flooded. I have an egress window, on the one end of my room, and on the other, my door and computer. Now when I say flooded, this isn't to say I had several feet of water. If that were the case, I'd have pitched my computer first thing in the morning, because it would be virtually useless. The most I ever had, at one point, was about an inch of water above the carpet.

My floor is angled in such a way that the water pools in my closet, and along the eastern wall, whereas my window is on the southern wall. My computer is also nearest to the eastern wall, so when I realized that I couldn't contain the water flow with our carpet cleaner (This is not my first foray into flooding), I immediately started removing items from the floor. My machine was one of the first things, as it's probably the most valuable thing in my room. The water line had reached my desk area, however it not actually reached my computer yet, although as I recall, it was damned close. While I was disconnecting it (I did power down everything first, trust me), I received a mild electrical shock from the monitor cable adapter, as I still have an older CRT monitor. I knew this is never a good sign, especially when water was involved, so I redoubled my efforts, and got it the **** out of there. What I had not yet realized, was that everything was powered down.

Now my setup works like this: my monitor is up on my desk, my machine sits on the floor, my UPS sits on the raised platform that your machine is supposed to sit on, and other various components are spread out on my desk and on top of my machine.

Now that my room is ready for habitation again, I went to reinstate my poor displaced computer to its rightful position of power (i.e. my UPS), and whilst plugging in my monitor to the adapter set in the video card slot, I received another minor shock. Obviously not deadly, but painful nonetheless. I checked everything again, just to make sure that I hadn't turned anything on by accident, but alas, nothing was turned on, except for my UPS.

I soon realized that this was the same thing that happened when I removed my case several days ago, so I quickly unplugged everything and went to work trying to figure out what went wrong. There appears to be nothing wrong with the case itself, putting it up on wood blocks, it still produces a minor shock, but only when the video-in cable is attached. Stranger still, it's only a problem when the monitor power is plugged in. The case can be unplugged, but as long as the monitor power cable is plugged in, and the video-in cable is attached to the video card, it produces about 14-16v shock.

The same thing happens when I switch monitors, and the monitor power cable. It still produces an electric shock. What I'm trying to determine is if my machine is at fault because of the flood, or if this is an unrelated issue that occurred as a result of my rough handling, or if it's completely unrelated to the night's events at all. I've discussed this with my father, and he thinks the likely explanation is that the video card is creating feedback, and shooting it through the adapter connected to the video card, which electrifies the case.

I run an nVidia 6600GT XFX card (AGP), with a 2.3 ghz P4 processor. 1 GB of RAM, etc.

I'd like to know if you guys can deduce a different problem, or other ways to find out. I'd rather not whip out a lot of money on a new video card if I can avoid it, or an entire machine, if that's the case.

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Old 06-27-2007, 06:53 PM   #2 (permalink)
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Default Re: Video Card Power Feeback?

With some more testing I determined that it's not the video card. I popped in my old nVidia 5200, and my fingers were still momentarily numb, and a number expletives also popped out of my mouth; partly because of the uncomfortable number of volts that traveled through my hand and arm, but also at the fact that I still have no solution.

Once again, I consulted with my father, and he thinks it's likely that my motherboard is fried. I find this unlikely, but the only logical deduction. The only other thing that I can think of, and the only other constant, is that I've been using an HDMI adapter for an old... what is it, 16 pin video cable? The latest non-HD hook up. I would go test this, however I've had my fair share of elctro-shock psychology for the day.

The reason why I don't think that it's the mobo, is that there wasn't enough water to get into the case, much less reach the motherboard. It's possible that the water shorted something else out, and that it caused a surge into the mobo via another cable, but the bottom of of my case is completely water stain free. The only thing that could have caused this was my subwoofer, which had water around and under it, but there doesn't appear any easy place for water to get into it that quickly.

As of now, I am completely at a loss as for what caused this to happen. It seems that my mobo is fried, and that the flood had nothing to do with it whatsoever.

I still can't be sure that my motherboard is actually at fault, however. If anyone has any ideas on other tests, that would be wonderful. I would start my machine up, but I'm afraid I'll need to use a fire extinguisher on it...

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Old 06-27-2007, 07:30 PM   #3 (permalink)
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Default Re: Video Card Power Feeback?

Upon further reflection of the amount of voltage feeding back into the case, I think I might have figured out the problem. The 6600GT not only uses the standard AGP power interface, but it also has a separate power requirement from the PSU. When I used a volt meter to see if current is running through it, I found that roughly 16V were coursing through the back case of my computer.

Now, when I replaced the 6600GT with my old 5200, I tested it again. It registered .4V - .5V. Of course when I touched it, there was enough electricity flowing through it to make me curse, but I realize now that there is no separate power requirement for the 5200, you only need to plug it into the AGP slot.

If the power was flowing into the PSU from the video card and mobo, then it may have been feeding back into the video card via the AGP slot and the power cable attached to the 6600GT. Since the power output was considerably higher for the 6600GT, is it logical that the PSU might be at fault?

I'm completely thinking aloud, and I apologize and congratulate all of you who have completely read through all of this. My question still remains, however: what seems most likely to be causing the electrical feedback?
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Old 06-27-2007, 07:33 PM   #4 (permalink)
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Default Re: Video Card Power Feeback?

wow thats a mouthful of reading, I'm pretty sure you have to give these things a day because there are other people who may know the answer but are on the other side of the globe

My computer uses 1.5A-load, .8A-idle, .65A-standby, .05A-turned off on 125V.
"The spaces between your fingers were created so that another's could fill them in."
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I need to stop using the internet.
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Old 06-27-2007, 07:45 PM   #5 (permalink)
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Default Re: Video Card Power Feeback?

Oh, I know. I'm plenty patient, but the way I figure it, if someone does read it all now, they may as well know all the facts.
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