ESD Problem

thepeach

Junior Member
Jan 13, 2007
20
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First, I'm having difficulty with ESD causing my motherboard to fail catistrophically. It has now occurred 2 times in essentially the same way - on the external portion of the case.

I'm hoping that the you Pros here can provide some helpful comments/suggestions for me to find the solution for my problem. Perhaps I've already found the problem but I cannot be sure. I've done the normal troubleshooting and checked out all that I know how to do.

I live in a dry climate, especially in the winter time.

If these two events had occurred while inside the case I would certainly understand the cause. However, with these two ESD events occurring on the external portion of the case, I assume that I must have a short somewhere but I just can't find it.

I built a new PC about 4 months ago and about 3 weeks after the build I pushed the "open/close" button on my DVD drive and a ESD caused the PC to powerdown. At first, I thought this had resulted in a digital fault and would clear by rebooting - but no such luck.

The front of the PC is plastic as is the front of the DVD drive. The PC is connected to a Belkin 1100VA UPS which is connected to an outlet that is grounded to a copper rod driven into the ground 7 feet.

I checked the grounding (using a digital multimeter) of the Case, Power Supply, the DVD drive and other components inside the case. I checked to ensure the outlet was grounded and it shows to be grounded. I did what I considered a thorough inspection of all grounding but did not find a problem.

All standoffs for the motherbaord to PC case have been verified.

The motherboard failed and had to be replaced.

About 3 months after this first event (a couple weeks ago now) I again reached to push the button on the front of my DVD Drive and a ESD arc occurred causing the PC to power off. The motherboard failed and had to be replaced again.

I repeated all the troubleshooting step of the first event and was about to give up when I decided to check the Ribbon Cables. ( I had failed to do this after the first ESD event).

The Ribbon cable that was connected to the DVD Drive had a bare wire exposed on pin 39 and another on pin 1 or 2. I have since changed the cable. I have also changed my PC Power Cooling 610 Silener Power Supply to a Antex NeoPower 550.

I've also changed out the DVD Drive and all Case Fans and taped over all unused molex connectors.

I've also installed a 3M Velostat Electrically conductive floor mat in front of my PC and desk which is grounded to the copper grounding rod.

Do you think the bad Ribbon Cable coupled with the ESD could have led to the failure of the motherboard?

Could it have been something with the Power Supply?

Can you suggests any further examinations or test that I might do or have done?

You're probably laughing your a-- off by now but I can't help it if I'm so very anal retentive. :D:laugh:

http://img248.imageshack.us/img248/5687/ribboncabletodvddrivewh5.jpg


 

Pwnbroker

Senior member
Feb 9, 2007
245
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I would have to guess that the naked wires were connecting with the case and/or electrical system of your pc, and you touching the open/close switch on your dvd just completed the circuit. There is no way to tell what damage has been done to your pc, but there is a good chance that something will fail early.
 

thepeach

Junior Member
Jan 13, 2007
20
0
0
Thanks Pwnbroker...Interesting comment...you might be spot on...

I forgot to mention in my post that the picture does not show it but I looked to see where the bare wire would hit and it looks as though the cable gets pushed up toward the top of the DVD Drive and actually folds back on top of it and the exposed wire hits (or is very close to) the metal case of the DVD.

Others have suggested that the PS might be the problem...It's a new PC Power & Cooling Silencer 610 that I have now replaced with a Antec Neopower 550. I used a multimeter to test the grounding on the 610 PS and it tested to be ok, Is there a sure way to test the PS to make sure it is not faulty in some way?

Thanks very much for the comments.