Grounding Issue

P

PolygonGTC

[H]ard|Gawd
Joined
Jan 6, 2006
Messages
1,791
I'm having a grounding issue that I'm having a tough time tracking down. This is happening in a build that I have had up and running for quite some time. It's vulnerable to static discharges. They cause it to either shut down or hard lock. It seems to be consistent with the top cover, but I've been able to replicate it by causing a static discharge on either side of the top, though it seems more resistant. I can't replicate it by discharging anywhere else on the case or chassis. However, if the case is fully assembled a static discharge to the top will not replicate the issue, but without fail will do it if you discharge on the front panel.

The specs are in my signature, on the left. Yesterday I really got into it. I have removed power for all the drives. I have removed the power/reset buttons and the front USB ports from the top cover. I've disconnected just about everything from the motherboard not required for it to run. I've checked to make sure there are no riser posts behind the motherboard where there are no screw holes. The power supply was tested before going in the system and it passed.

However, I've sleeved all the cables with MDPCx. I did them one by one just so I couldn't mess up where they go. And I've done it before and never had problems. But I don't think that could be causing this. I would think it would have caused some serious damage right off, or not powered on at all. I was going to try a different power cable next and then a different outlet. Beyond that I don't know what it could be besides the system board or the power supply.

Does anyone have any suggestions?
 
Nope.

What would be the easiest method to do that? I have a multi-meter and I assume you could test that at the ground at the breaker? I'm just not too familiar is using a multi-meter.
 
Where are you? If you're in North America or another place where the typical wall outlet puts out 120VAC, measure between the narrower hot prong (shown in red here) and the ground prong (shown in green). Your meter should indicate about 120VAC between those prongs if you have a ground connection. When you measure between the ground prong and the other, wider neutral prong (shown in blue), you should get about 0VAC, unless the hot and neutral wires are reversed (should not affect computer).

7_outlet_wiring.jpg


However, you may have to poke around and scratch the contacts quite a bit before you get a valid reading, so don't assume that a zero reading means no juice. Also it can be dangerous to measure high voltage, and I had a Harbor Freight meter lead pull out when I tried to measure an AC outlet, causing the lead to show exposed metal with high voltage riding on it.

Another possibility is an AC cord with a broken ground connection.
 
Thanks!

I'm in the U.S. I'll give that a try. I was also going to try another cord as well.
 
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