Very unuasual PSU problem

[humbug]

Instead of writing it again i'll just quote myself.

Check the three 12v PCIe power pins in the 8 pin plug, if they are black you have a problem with the PSU.

I had an issue with my PC Black Screening, it got worse over time, eventually the PC just wouldn't start, GPU error lights and beeps.... its would work for a while if i unplugged the PCIe power cables and put them back.

To cut a long story short i though it was the GPU and replaced it, after a week or so it started doing it with the new GPU, after close inspection i noticed the three 12v pins on the new GPU had started to darken, so i looked at the old GPU and the same pins were black, i cleaned the pins on the old GPU and it worked again....

I have now had a new PSU for a week and all is fine. touch wood.

this is the post i made when i first started having these problems.

http://forums.overclockers.co.uk/showthread.php?t=18681871

Has anyone ever had this problem? what causes the 12v PCIe pins to go black like that and block the power feed?

Offending PSU was an XFX 750 Pro, 4 years old.

 

[Robert_G]

I think I had the same problem, but in a different place (if I'm understanding you correctly).
For me it was an ATX 12V socket that supplies power to the CPU though.

It's caused by loose connections. You end up with oxidisation where the electricity arcs on the connector, this in turn increases resistance and causes the connector to heat up.

I have a thread with images here: http://forums.overclockers.co.uk/showthread.php?t=18652099

I ended up having to solder a new socket onto the motherboard.

Edit: The damage to that plug happened in a pretty short period of time too, as it hadn't long been rehoused in a new case.

 

[humbug]

No melting of the plugs or socket, the discolouration of the pins also didn't go outside the socket, IE under the socket and into the PCB was still clean and silver like the rest of the pins. it seems to have been only where the plug was attached.

 

[Mr Evil]

It could get hot enough to cause the pins to oxidise without getting hot enough to melt anything. You could verify that the connection is poor by putting a load on the GPU for a while, then carefully touching the connector to see if it's hot.