New Seasonic Power Supply Issues

bloomingnutria

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Jan 18, 2013
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Hi Everyone,

The other day I installed a brand new Seasonic X750 (first generation) PSU into a very bare bones system. The only thing it consists of is a Biostar A770E3 motherboard with a Phenom II X4 cpu, 8 GB od Mushkin RAM, an Nvidia Geforce 8600 GTS graphics card, and one hard drive. There is also a firewire card, and the two small fans that are built in to my Antec P280 case. There are no peripheral drives attached at the moment.

And of course I do realize that this is way more power than I need for what I have, but I am planning to expand my system in the near future.

Anyway, when I first hooked up the PSU, everything worked fine. It booted right up and worked flawlessly for a whole day. Then the following morning it booted up as well. However, in the late afternoon I noticed that the computer was off, and I hadn't turned it off. I dismissed it, thinking maybe my two year old had done something (unlikely, though).

Then, I booted it up again that night, and although it had power initially, it cut out a few moments later during boot. When I tried to turn it on again, it had no power. I checked the connections inside and wiggled some cables around and tried a few times more, and each time, it would get power for maybe a half a second (just long enough for the case fans to spin) and then cut out.

So I am now wondering if this is a faulty PSU, or if there is maybe something else going on. My technical prowess extends to putting working components together and troubleshooting basic things, but in truth, when it comes to dealing with actual electrical current, I'm a bit over my head. I would appreciate some guidance.

If there is any kind of equipment I need to buy in order to test the function of this PSU, just tell me what it is and how to use it and I'll do it. I want to learn how to deal with things like this in the future.

Thanks in advance.



 

bloomingnutria

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Jan 18, 2013
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Thanks for your reply! I don't have another PSU at this moment, but in a couple of days a new Seasonic will arrive from Newegg. There was a deal on the X850 last week that I just couldn't pass up.

And no, nothing is overclocked.
 

bloomingnutria

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Jan 18, 2013
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It was an existing system. I had it in a basic no-name case with a generic 550 watt PSU, and the PSU went bad a few weeks ago. One day it just started clanking because the fan was banging against something in there, so I ordered the Seasonic. I had a new Antec case sitting in my closet and just transferred everything in there.

Since basically all I had to do was pull out the motherboard and the hard drive and screw them into the new case (my DVD drives went bad some time ago, and had been disconnected for months), there really wasn't much room for error.
 

COLGeek

Cybernaut
Moderator
I would recommend you completely disassemble the system and check all of your stand-offs/mounts for a possible short condition. Also, make sure your ATX I/O plate doesn't have any small tabs protruding into a port.

Also, make sure your RAM is firmly seated and that the heatsink if firmly attached. Any of these things could have been dislodged when you did the transplant and could be causing the problem.

Good luck!
 

bloomingnutria

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Jan 18, 2013
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I'm not sure what you mean when you say "check all of your stand-offs/mounts for a possible short condition. How do I do that and what exactly do I look for? Could you explain?

Thanks!

 

bloomingnutria

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Jan 18, 2013
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Oh, and I forgot to add that at one point yesterday when I tried turning it on (after it had been off for a long time), it did boot all the way up. Then it just cut off again. Thanks again.
 

bloomingnutria

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Jan 18, 2013
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Okay, thanks. No, I have not been home to check those other things yet. I just wanted to make sure I understood what to do. I will check all of it first thing tomorrow morning and let you know.

Thank you!
 

bloomingnutria

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Jan 18, 2013
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Well, it worked for about ten minutes and then shut off again. Here is what I did.

First I rechecked all of the cards and heatsink, and everything was seated very firmly. Then I took it all apart out of the case. There was one screwhole on the motherboard under the graphics card that was not connected to anything, because there was nothing to screw it into on the case. But I saw that Antec had provided some extra little metal mounts to screw into the case. I put one it where it was supposed to go, screwed the motherboard back in again, and made sure everything was seated as it should be. But unfortunately it didn't make a difference.

Now I have to ask you what may be a silly question. Does it matter tremendously what kind of screws you use to attach the motherboard? The first time, I attempted to use the smaller screws with round heads and the little flattened metal rim that is a part of the head, which I thought were supposed to be for the motherboard. I have always used them for that before, anyway.

But they just kept turning and turning and never seemed to tighten (the threads seemed too densely packed and shallow), so I ended up using the larger screws that also have a round rim, but the head itself is a rounded hexagon. They're the ones I always used for the outside of the case in the past.

Those went in and tightened fine, but today I noticed that they have ridges underneath the heads (to "grip" better I guess) that may have been preventing a good contact on the board. I had them screwed in firmly, though.

Anyway, today I thought that may have been the problem, so I managed to find some screws that went in firmly and had a flat underside to make good contact with the motherboard. When I turned on the computer and it booted right up, I was hopeful that the problem might be solved, but like I said, I lost power again.

I am very grateful for your help!

 
Make sure you don't have any extra motherboard standoffs installed on the motherboard tray that don't match up with a mounting hole on the motherboard. Any extra standoffs will cause a short circuit causing the power supply's short circuit protection circuit to kick in.
 

bloomingnutria

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Jan 18, 2013
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No, there aren't any extra. That was one of the things I checked the first time.
 

bloomingnutria

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Jan 18, 2013
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I installed a new X850 and that seems to have solved the problem, so it must have been the PSU. I will have to RMA it. Does anyone have some insight into what actually may be wrong with it?