Computer Is Chain Restarting.

[MIDItheKID]

Okay, here's the specs:

Intel i7 920
ASUS P6T Deluxe (v1)
6gb Corsair DDR3 XMS
GeForce 260 Core 216
Corsair 750w PSU
2x 500gb WD SATA drives (no raid)
Pioneer 112d DVD-RW
Sound Blaster x-Fi Platnum

Here's a basic description of the problem:
When I hit the power button on my computer, it powers on for about half a second, then immediately powers off. If I keep my finger on the power button, it will do this over and over and over again. Strange thing that I want to note is that even if I press the power button once, it will go through this on/off cycle 3 or 4 times before "giving up". Sometimes if I keep trying (takes about a half hour or so), I can get it to power on, and it will stay on and run relatively smooth, but my USB hard drive will act as if it is unplugged, and in order to have my computer recognize it again, I have to unplug it, and plug it back in.

This is when it happened:
I had the rig running fine for about 2 months (built it in december). And i built it inside of an old case that was a really tight squeeze for that monster sized video card. So I decided to buy a new case. I swapped all my parts into the new case, and it booted up like normal. I then left my computer on and went out for the night. I came back home and my computer was off, and when I tried to power it back on, that's when it started doing the chain restarts.

What I have tried:
First thing I tried was taking out all the non-necessary parts (HDD/DVD/Sound etc...) Still had the issue. So then because I wasn't even getting a POST, I decided to strip it down even more. I removed the video card first. Still same chain restarting. Due to the fact that the last modification I made to my rig was the new case, I thought it might be a grounding issue. So I took the motherboard and PSU out of the case with the CPU and the RAM still in. I placed it all on a large wooden table in a room with no carpeting. I then tried again, same problems. I thought maybe it was a defective power cable, so then I swapped it for another one. Still the same problem.
At this point I started freaking out a little. I thought maybe it could be one of those funky RAM problems so I took out the RAM thinking to myself - "Well if it's the ram that's making it happen, I should at least be able to spin up the processor fan by powering the board on". But still, no go. Now I was down to 3 parts, mobo, PSU, and CPU. I decided the next step was to take the CPU and CPU fan out. I did this, and was left with a dry motherboard hooked up to the PSU.

One side note i'm going to add in that I forgot to mention earlier is that the P6T motherboards have an on board power button, so the case, or any other kind of power switch has been unplugged for quite a while at this point (rules out a faulty power switch).

So here I am. Power supply and motherboard only. Now, the motherboard chipset heatsink has a neat little neon light on it, that shines nice and bright when the computer is powered on, so this is what i'm using to tell if it's booting up right at this point because there are no fans besides those in the PSU. I hit the power button aaaaand... still the same problem... On for about 1/2 a sec, then off for a 1/2 sec, then on for 1/2 sec, then off for 1/2 sec. Ouch...

Alright. So because I was down to 2 parts, I went to a friends house. He has a almost identical rig (we built them together) and I asked if I could plug his power supply into my motherboard and test it. So I did this. And the same problem happened. I then plugged his PSU back into his computer and it still functioned fine.

At this point I thought I had figured it out... It was the motherboard, right?
Wrong!? Maybe?!

I RMA'd the motherboard and was a little suprised when ASUS sent me another V1 of the P6T Deluxe (due to the fact that V1 is no longer being manufactured). When the new one came in the mail, I hooked it all up, and still have the same exact problems.

At this point i'm not even sure what to do. The only thing I haven't really tested is putting my CPU in my friends rig and seeing if that might be the problem. But even if it was the CPU, wouldn't the mobo at least power on? I mean... If I take the CPU out, it still has the same problem. And last time I checked, if you power up a mobo with no CPU in it, it will at least spin up the fans.

I made sure to double check all my power connections too.

And because I couldn't figure out what else it could be and I narrowed it down to 2 parts, I RMA'd my power supply also.

That came in the mail, and still the same issue.

Please help... I've been without my baby for almost 3 months now, and I use my computer as my Music Production Station, Work Station, and Play Station. I don't even know what to do without it.

Thanks for your time if you read through this whole thing.

Oh, and it's not a heat issue, because it still has the same issues after being off for over 8 hours (no heat). Not to mention when the problem happened, I had just put it in a new case that is HUGE with 4 120mm fans... plenty of cooling.

 

[JoshSB]

Wow, that is a helluva problem.

You do not get any POST beeps with everything plugged in but say the RAM?

Have you checked if there is something connecting the case and the motherboard shorting it perhaps?

To be 100% honest I really have no idea what your problem is... You have tried a different outlet I assume?

 

[Snake91839]

I would bet on motherboard shorting out. Make sure all the standoffs are in the right place, and that you have all the standoffs in. and make sure non of the components are touching the case.

 

[Sheepykins]

well when when i was reading it through i too thought it was a grounding issue and that you had fried the motherboard by accident, but if they sent you a new one and also a new power supply then hmm.

so basically just plug the mobo into the psu and put the processor in, see if its still doing it then you've narrows it down to three components because yeah if theres no processor in there then POST should beep 5 times fast (i think its 5 times fast) and if theres no beeps then its one of the 2 you have there.

did you try your power supply on your friends computer? or any other in your house. if it works then its not the power supply, just sounds like a board issue to me, it wouldnt surprise me if asus sent you a duff board by mistake.

 

[carnageX]

well when when i was reading it through i too thought it was a grounding issue and that you had fried the motherboard by accident, but if they sent you a new one and also a new power supply then hmm.

so basically just plug the mobo into the psu and put the processor in, see if its still doing it then you've narrows it down to three components because yeah if theres no processor in there then POST should beep 5 times fast (i think its 5 times fast) and if theres no beeps then its one of the 2 you have there.

did you try your power supply on your friends computer? or any other in your house. if it works then its not the power supply, just sounds like a board issue to me, it wouldnt surprise me if asus sent you a duff board by mistake.

You have to have: RAM, CPU, Video, and PSU for basic components in the motherboard to get a POST.

 

[HAVOC]

I would bet on motherboard shorting out. Make sure all the standoffs are in the right place, and that you have all the standoffs in. and make sure non of the components are touching the case.

I realize that his post is lengthy, but he did address that already. If you read the full post you woul dhave seen that.

Anyway, this is the type of situation that will make you jump off a bridge. God, I've had those PC issues before.

Wacky question: The power supplies you are using do you have them plugged in to a "power strip" when you are doing your troubleshooting? Are you plugging the power supplies directly into the wall outlets? Various wall outlets?

 

[MIDItheKID]

I've tried both regular wall outlets and through a power strip.

I've done a lot of reading about the P6T motherboards and ive heard that they have about a 50% failure rate.

I'm hoping it wasn't a faulty power supply that messed up the RMA'd mobo, and now i'd have to replace it again.

Once again to note, it's not a grounding issue. I've been trying all this stuff out of the case.

and as far as POSTing goes. That's not what i'm trying to do. I'm trying to get it to turn on and stay on. If I can get it to do that, and it doesn't POST, then i'll work on it from there. But my main concern is getting it to stay on all the time.

I feel like it's something simple and stupid though because i'm writing this post FROM the computer that is doing the chain restarting. Like I mentioned - if I sit there for about half an hour and keep hitting the power button, and flipping the PSU on and off, and power button and PSU on and off, eventually I can get it to boot up.

That's why I feel like all the hardware SHOULD be working fine. If it was a serious processor error, I don't think the computer would boot at all. The same with a grounding issue. If it wasn't grounded properly, then why would trying over and over again make it work?

I'm going to get a magnifying glass and inspect all the capacitors on the motherboard. I have a weird feeling one of them is leaking. It's the only thing I can think of that would produce results where it SOMETIMES works, but 95% of the time doesn't.

So confusing and infuriating.