Plug into front of new case kills computer

jj_rice

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Feb 7, 2010
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Recently built new system and have an annoying problem. If I plug anything in the front I shut down the computer. Contacted the case manufacture Antec who believed it was a ground issue with their front panel. This was the same conclusion Gigabyte Motherboard manufacture reached. They mailed a new strip which I installed in the front panel, same problem. I don’t have to plug in, just barely touch the jacks with the male plug knocks the computer down. Touch the audio jacks or the e-SATA or the USB get the same result. Plug in before powering up and they work. I should mention that if I plug anything in the back of the computer I don’t have this problem. Any Ideas?
Antec Sonata Elite case with a GIGABYTE GA-MA785GMT-UD2H and AMD Athlon II X2
 

jj_rice

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I checked and rewired the new strip Antec sent. It would appear to be a grounding problem. Wanted to jack in my headset. By just barely touching the jack, it knocked down the system. I then shut down the system and then plugged the jack in. I noticed my monitor reacted to the plug-in even though the computer was powered down. Powered up the system and everything worked. The audio is connected to a different part on the motherboard then the USB. When I just touch the outer case of the male USB to the outer case of the female USB this too knocks down the system. Again If I plug in before powering up it works ok.
 

jj_rice

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LCD had black screen no signal but when I jacked in the headset the screen lightened as if it was getting a signal and then darkened. All in power down mode on the computer.
 
What are your full system specs and do you have access to a digital multimeter? For the audio jack to cause it it leads me to believe that your case may be hot not ground like it should be, i would use a DMM to check the voltage between the case and the shield of a USB port when the system is on, it should be 0 as they are both supposed to be ground, if it is not then you have a major problem, likely PSU related.
 

jj_rice

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My problems stated several months ago. I lost a motherboard and decided to build new including a new case. My old system was occasionally giving my static shocks. Thought it was dry winter air. Well last night a thought came to me. Last fall we replaced the sewer and water supply to the house. It was after that point I was having problems. It could be just a cruel coincident. The plumbers reconnected the house ground to the new copper water pipe. There may have been some film on the copper pipe. I will be looking into cleaning the house ground connection.
 

Paperdoc

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You are right to pursue the house Ground connection as the suspect. The latest electrical code in some areas actually requires that the house main Ground be established separately and you might need to go there if all else fails. But most homes are using the water supply line into the house.

That supply line only works because the pipe coming through the floor is actually the end of a long bare metal piece of pipe buried in the ground. It depends on contact of metal pipe surface with soil over a large area. If I read your post right, it was that buried pipe coming into the house from the street water main that was replaced. If the piece of new pipe was coated with something to prevent soil contact and make it last longer with reduced corrosion, or had an insulating wrap around it, or anything like that, it does not provide the contact area needed. On the other hand, if the piece of pipe coming up through the floor is actually joined onto the buried pipe under the ground with anything that does NOT preserve good electrical contact, you don't have the long length of buried pipe needed. So, check with the plumbing contractors for details of how that water supply pipe was installed.

You are right, though, to start with the connection to the new pipe. It is usually some simple two-piece metal saddle fitting that tightens onto the copper pipe with bolts. It then has a hole with a large setscrew to connect the Ground wire from your breaker box. If the fixture itself looks old and corroded and hard to clean, just buy a new one at any electrical supply or hardware store - easier that cleaning sometimes. But you might be able to clean the inner surface of the saddle fitting with emery cloth or steel wool or a wire brush. Similarly, use a piece of emery cloth to just polish the copper pipe in that short area before re-installing the saddle. Also look closely at the end of the copper wire, to be sure it is clean (and the inside of the saddle's hole) before re-assembling and tightening the setscrew. Don't forget, the setscrew and saddle clamp bolts do not need to be super-tight - they only need to be tight enough to bite into soft copper a bit. You don't want to puncture or squash the pipe!

When you investigate you might find an obvious dirty or loose Ground clamp on the pipe. But if you don't find and fix something obvious, consider having an electrician check that the quality of your household's master Ground connection is good enough.