2 separate AX650 PSUs failing to power up PC, very strange problem, please help!

NShukla

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Jan 13, 2010
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Hi guys, I'm asking for help here because I've already tried google and Corsair RMA.

I have an AX650 PSU and started having issues with my PC not powering up when pressing the power button. The power supply 'clicks', all the fans start spinning up and after 0.5 seconds it clicks again and the fans stop. The power button's LED fails to turn on. All the USB power works though (my external spins up). The only way to get the PC on is to try a combination of resetting the CMOS button on the mobo, or switching the power supply off and on, and then it only works randomly after 6 or 7 tries. When it does finally work, the power LED turns on. No problems when the PC is actually on. Everytime I start the PC from a cold boot it has this problem, although randomly, and only when the shut off is clean, it will power up just fine. But not every time!

So I swapped the PSU with an Antec one I had. NO PROBLEMS. Powered on just fine. So I sent in the AX650 for RMA. I got the new unit a few weeks later, wired it up with the new cables and everything. SAME EXACT ISSUE! Swapped it out for the Antec again: NO PROBLEMS!

So my question is: why is the PSU, which is universally praised for it's high quality, failing to work properly in my build. It's a modern build, the specs are below, no overclocks done or any other BIOS mod:

-Gigabyte Z87-UD3H Mobo
-Core i5 4670k
-Corsair Obsidian 550d
-Corsair AX650 PSU
-8GB DDR3 Kingston HyperX RAM
-AMD Radeon HD 7870
-Samsung Evo SSD
-Cooler Master Hyper 212
-3 SATA hard drives

Very irritated because I specifically sprung for the AX650 because of it's high quality. It can't be a dud either because I've already RMA'd and the new one failed! There can't be problems with the power switch because the Antec PSU worked flawlessly. If it's the PSU, why isn't it considered bad by anyone? Thank you so much for any help, I'm tearing my hair out here!
 

MaXimus421

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Jan 22, 2012
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Sounds like you received two dud PSUs in a row. And yes, that CAN happen, maybe a bad batch. At least Corsair stands behind their products. Send it back. Explain your situation. They might send out a larger unit [750+] just for your troubles, which isn't unheard of either.

Sometimes these things DO happen. GL.

Edit: Better yet, try testing the PSU in another system if you have one available to do so. Troubleshoot...
 

NShukla

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Jan 13, 2010
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Update: So I just finished building an AMD FM2+ MicroATX (Gigabyte A88X-D3H mobo) build, and decided to test the dud AX650 PSU with it. It works wonderfully! No issues!

Perhaps the AX650 is incompatible with Haswell or Intel. I'm going to buy a new one, but I'm still curious what the source problem was.