Weird Corsair 750TX problem

I need a response quickly as we may leave soon to buy a different power supply. Obviously it would be ideal to just use the working corsair 750TX. In total I've had 3 dead corsairs.

The first was doa, the second actually caused some flames to appear I believe in the power supply and the third is not broken necessarily but it won't boot right off the bat.

They were all tested with paperclips prior to installing them into a computer with the first failing out of the box and the second one failed after 8 months.

The 3rd one will not boot it up if connected to the motherboard's 24 pin connection. Currently I am using a second power supply to power the motherboard's 24pin connection while using the corsair to power everything else. If you look at my system below you'll see that I definitely do not run a heavy load, I chose corsair for sound levels and stability. So far they have been very quiet but I'm having some serious issues with reliability. The 3rd still spins it's fans and can adequately power components fine but will not power anything if connected to the 24 pin motherboard.

If the 750 is connected to the main motherboard it will not spin fans or boot. It appears to begin to boot for 1/4 a second, fans spin slightly and leds flash. There is no short/sparks or anything like that. I get the power led on my asus p6t lit up when connected. If I connect any other power supply to the 24pin it will boot up so it definitely is not an issue with my build. Do I really have to pay another 20 dollars to rma it? and is there an option to permanently return it for money considering this is the second time it's died? I just want my computer to work .

It seems like the connector to the motherboard is damaged ( no damage visible on the cable ), that's my best guess at least. Thanks for reading my long post.

Motherboard asus p6t SE
Processor i7 920 @ stock
Memory 3gb DDR3 1333mhz
Video Card 9600GT passively cooled
Hard Drive intel SSD 80GB
Optical Drive blu ray reader/dvd burner
Power Supply corsair 750TX
Case silverstone fortress
Monitor 24 inch samsung @ 1920x1200
OS 32bit windows 7/vista
Flash Drive 16gb

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