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Very strange line power issue with HX850!


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Hi all, I have quite a strange issue I'm hoping someone can help me with. I built my system back in August of last year (specs in profile). Since about early December I have been having an issue where occasionally my system will not power on. After hitting the power button the fans will spin up but the system will just turn on and off very rapidly. There are no POST beeps nor anything displayed on the screen. When this happens I can usually get the system to boot by switching off the PSU and trying again. This would sometimes require multiple attempts. At first I thought this may have been a motherboard issue, but since it only happened sporadically I had put off doing any RMA's.


Now this is where things get strange. For the past week I have had a new problem with lights in my room flickering when the PSU is under high load. Mind you, I'm not talking about lights inside my case/computer, I'm talking about actual lights in the room! I have never seen anything like this in my 15 years of tinkering with computers.


When this happens, the system keeps running as if nothing abnormal is happening. Internal voltages all seemed normal as well. I measured the power draw of the system using one of those "Kill-a-Watt" meters. The flickering doesn't start until the system begins to draw about 550 watts. The system peaks at just under 700w. At first I thought it may have been a problem with the household wiring, but nothing has changed since I built this system. I tried switching the HX850 with a TX750v1 from an older system. With that PSU installed I no longer get the flickering lights when under load, so I'm pretty sure the issue is related to the HX850 itself. Using the TX750 also seems to have corrected the power-on issue I was having originally. I haven't had that problem since swapping the PSU.


Sorry for the long post, but I have never seen anything like this before. Any advice on what to do would be greatly appreciated!



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If changing to a different PS solves ALL the problems, then the other PS is obviously the culprit, as long as you used the same AC cable and plugged the PS into the same AC outlet. Unless there is a cable problem that is causing a short, etc, when using the 850, which is hard or impossible to test on all the cables. You could put the 850 back in and see if the problem comes back.


If the PS is bad, you should RMA it, people have RMA'd units for "issues" a lot smaller than that.

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i had the exact problem with my 750hx and no post but everything else is working.

did you check if your cpu or your video card actually works when you powerup with your 850hx?


because mine wasnt powering up the cpu at all, with CPU LED warning on my motherboard.

it turns out that when i bend the big 24pin connector a little bit it works again.


heres my thread about this http://forum.corsair.com/forums/showthread.php?t=104438

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Thanks for the replies. Just wanted to post an update.


As was suggested I went ahead and opened an RMA. Corsair techs had me try a few things like different power cords, moving the PC, etc. Nothing seemed to really help. One thing I noticed is that the flickering is most noticeable in florescent lights (both CFL and regular). Very strange.


I have been doing some more reading online. From what I understand, it may be a fault in active PFC circuitry of the unit. But that is just a total guess.


Corsair RMA support has been awesome. So hopefully this was just a random bad unit and the replacement will be A-ok.

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