Burnt ATX connection, ever see this?

[timbob2469]

My 8RDA+ ver. 1 turned off this morning, so after work I put it up on the bench, started posting then I noticed the 80 port LED with postcodes was erratic in light intensity, like it had a loose wire/power failing. It kept on reseting before bios setup, memtest86, or windows would load. Same flickering LED. So I gave the ATX connector a slight nudge then pushed down on it to make sure it was fully seated, and VOILA! the flickering LED became a steady glow, and memtest86 started. I shut it down and unplugged the ATX connector, Yikes! Either this connection was arcing or ....what? Any comments and suggestions how to fix this would be appreciated.
Bob
ps. The caps look good AND I see all the crud on the NB fan, it had been folding for about 4 weeks straight, running 15 hour days.

[Gizmo]

Dude, those are the pins carrying the +5 for your mobo! It looks like you've been OCing this board, and it pulls all the VCore off the +5 bus, so you've nuked your connectors. About the only thing you can do is find where those pins come through the bottom of the mobo and hard-solder the wires from the PSU directly to the mobo at the pins (being careful not to short anything).

[smiffy]

Hi Timbob
Exact same thing happened to my 8K7A when I plugged a gf4 4600 in it.To much current through the 5v connectors and I suppose after a while they crud up increasing the resistance through the connectors making the problem even worse.
Smiffy
Looks like only real option is as Gizmo says,solder straight to board,I gave up and dumped the whole lot in the pin but mine was in a bit worse nick than yours.

[timbob2469]

Thanks for the feedback. Any guesses why this happened? Would a carefull application of die-electric grease help to avoid this on future builds? It is an Enlight psu that was/is being used 98% of the service life, I tested an Antec TC550 for about a week or so before moving that to my main rig. I guess it is time to get out the soldering pen, Might as well try the memory voltage mod while I have it out. This had to have been one of the real early 8RDA+ boards, I ordered it like the minute they started taking orders, I still have the box, the serial # ends in 000143. If this were a Monty Python Movie the board would be saying, "I'm not dead yet". I might have to put a different ,less stressful cpu , run it default speed, and send it to college with my daughter.
Bob

[Gizmo]

I don't know what those connectors are rated for current-wise, but I would be surprised if it were more than 10 amps/pin. All you have to do is pull close to the max rating for a while, and you'll oxidize the connectors enough to start causing an increase in resistance. Once that happens, you've got a self feeding cycle.

[timbob2469]

I think I recall SANDRA reporting that the cpu alone was drawing 100-102 watts and if that is being fed off of the 12v rail =8.5A ....
running 2 X 256 MB ram modules at max 2.88v , gf4-mx440 pulls a lot also. When I used to work on cars I remember they (the factory) would insulate electrical connectors like this with some type of grease, I have some conducting grease from installing ignition modules, that's why I asked about that stuff. I can't be the only person with fried connections, I wonder if the combination of things caused this:
1. 8RDA+
2. Enlight psu
3. Overclocking
4. GF4 mx440
Have you checked your ATX today? (Or maybe this year).
Bob

[Gizmo]

When I was in the video game business, we used to see baked down connectors like this all the time. See, any electrical connection has some intrinsic resistance. When you are pulling 40 amps, a .1 ohm resistance in the connection equates to 4 watts of power. 4 watts of heat with a dissipating surface that small and no air flow means a lot of heat. In practice, the resistance of the connection is usually quite a bit lower than that, but you get the idea.

The reason automotive manufactures use dielectric grease on their connectors is to prevent corrosion caused by a harsh environment. I highly doubt that it would have prevented any problems in this case.

[timbob2469]

So I guess the culprit would have to be the psu, or more precisely the resistance in the ATX connector supplied with the psu. Antec uses gold plating on their connectors for a reason, now I think I know why. I'm probably going to get one of those 12" atx extensions and hard wire that to the board. I wasn't really running an insane overclock, and I'll bet there are more computers with this happening. I'll have to add "check main atx connector" to the list when doing routine maintenance like clearing off the fans and blowing the accumulated dust off everything in the case. Thanks again for the help trying to understand this problem.
Bob

[Gizmo]

Actually, having those gold plated connectors makes the problem worse, not better. See, the connectors on the mobo are tin. You have to have a like to like connection (gold on both ends or tin on both ends). If you have a situation where the connectors are of different metals you can end up with what's called fretting corrosion, which is where the hard metal rubs the soft metal off. Now you've got a worse problem than you had before.

[robbie]

You may wanna try some DeoxIT. I use to use it on some of the copiers I work on all them time. It really helps with corrosion. Link
Rob

[Aedan]

Originally Posted by gizmo

If you have a situation where the connectors are of different metals you can end up with what's called fretting corrosion, which is where the hard metal rubs the soft metal off.

Or worse, if there's any moisture in the air, you set up a small galvanic cell which sets the connector up for corrosion at higher speeds. Mating connectors should always be made of matching metals, whatever the connector is. That includes DIMM sockets, PCI & AGP sockets, as well as ATX connectors!

As far as I understand, in automobile applications, the grease is there to protect the connector from the harsh environment it's in. It helps keep salty water and the like out of the connector. Introducing those to a connector will corrode it very quickly!

[Woof!]

Yep, have seen that happen to an Enermax PSU with - guess what? Gold Plated connectors! I'd agree with everyone that it's the different materials the connectors are mated on that's causing the increase in resistance. The fellow just had a technician replace his entire connector block and everything worked fine again.

Hmmm, come to think of it, I actually remember seeing some older mobos with gold plated ATX connectors...

[muddocktor]

Originally Posted by Áedán

As far as I understand, in automobile applications, the grease is there to protect the connector from the harsh environment it's in. It helps keep salty water and the like out of the connector. Introducing those to a connector will corrode it very quickly!

I disagree with you on that last sentence. Unless there is some kind of reaction between the grease and the metal in the connection, the conductive grease should help keep the connection from oxidizing by not allowing any moisture penetration to the metal surfaces. It won't help conduct electricity better but it will prevent deterioration due to oxidation from a moisture/oxygen mix.

[EPoX Tech]

I think what you are stating actually agrees with what Aedan wrote.