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WillThomason

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Computer will only turn on when you reseat the motherboard power supply connector

I have never been more stumped. I woke up this morning and everything in the house was turned off, i assume the power went out. I turned everything back on and had no problems, except with my home server. It would turn on as if it were going to boot, but nothing would ever appear on the screen. Fans and harddrives were spinning and lights were turned on normally. I first checked the monitor and it would good, then i checked the video card and it was good. Then i tried using a new power supply from another computer and it still would not boot, even when i brought the PC down to bare minimum parts. I also tested the RAM and ram slots.

I assumed the motherboard or CPU were dead, and decided it was a good time for an upgrade since its tax free weekend. I went out and bought the 8 core amd cpu 3.1 ghz and the ASROCK 970DE3/U3S3 AM3+ ATX motherboard. Installed them and everything started working great, then after 3-4 reboots to install drivers the problem reappeared! I went through the same steps and decided it had to have been the power supply that fried the old motherboard and thus has fried this board as well. I went out and replaced the motherboard and got a new corsair 750w power supply and installed them. The computer turned on but the very next time i rebooted the problem returned!!

After playing around with it as much as i can, i have learned that the computer will only boot after i have taken out the power supply motherboard connector and put it back in. Once i take it out, the moment i put it back in the computer boots up normally and works, even if i dont press the power button on the computer.

I am so confused, any idea what is going on?
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Erdinç Güngör Çorbacı
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i think you may need to change capasitors or if you can send for warranty.
(if you can after trying with another PSU)
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It is probably a corrupt boot sector in the OS (caused when power went out?) that may be difficult / impossible to trace.
I had a similar PC  that was resolved by a fresh OS install.
some possibilities :
1- bad capacitors, as suggested in mobo or PS; but since you replaced both, it seems unlikely
i assume you use d parts and devices from the old setup - if so, which ones did you reuse?
the problem has to come from one of them

in such cases, i test each part carefully, starting with ram and disk
use the dmemtest86+ for ram, and the diag for your disk brand
best download UBCD to run diags
 
http://www.ultimatebootcd.com/                              ultimate boot cd
http://ubcd.mirror.fusa.be/ubcd511.iso                        direct link UBCD
Must say i agree with nobus.

Also check that there are NO USB devices plugged in (Printers, Hard Drives, etc...) i have seen instances where some printers that are plugged in via USB cause system to hang at boot as the system tries to boot from the USB printer memory. Usually a MOBO firmware upgrade fixes it. I am surprised that you would have the same issue on 3 different mainboards but you need to narrow this down.

Cheers
Andrew
< Once i take it out, the moment i put it back in the computer boots up normally and works, even if i dont press the power button on the computer. >

This suggests that the power cord is live and still plugged into the PSU when you plug in the motherboard connector - not a great idea...

If you've done this with every board, it's quite possible that each one has been damaged in the same way, and it's also possible that the PSU has suffered similarly.

I would suggest that yet another new PSU and motherboard, fitted and connected in the complete absence of electricity, and with due attention paid to anti-static precautions, is likely to put an end to these problems.

If I've misunderstood your statement, first check in the power settings section of the BIOS that the system is set to stay off in the event of a power outage.
Next, take the cover/side panel/whatever off the computer so that you can see the flea LED on the motherboard that is lit as long as power (even standby power) is applied to the board, then switch the power off at the wall socket, leaving the power lead plugged in.
Then press the power button a few times until the flea LED goes out.
Next, leave the computer to sit for an hour or so to give the PSU capacitors time to discharge as well.
Finally, switch the power on again at the wall socket; the computer should not power up at this point - it should only come on when you actually press the power button.
and consider the possibility that you have more than 1 bad device...that's why i suggest to test everything carefully
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WillThomason

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Thanks for all of the suggestions, i tried booting with no USB devices and that did not work. I also had the motherboard set to power on if there was a power failure, i turned that off. The problem remains. I am being careful about static electricity, i have the wrist guard. I do not think it is a harddrive/os issue as when i press the button i get absolutely no feedback from the monitor and the computer refuses to POST or even get to the bios screen. If it were the os/harddrive it would seem like it cant even get to that point. Even if i take the harddrives out totally it gives the same issue, when it should at least boot to the bios.

I am testing the memory now as suggested.
It is also worth mentioning that i left the server on all night and this morning and it continued to work and didnt have any issues. It runs 5 VM's also so out of the 8 gb of ram almost all of it was being used.

Hardware seems fine, just wont boot from the power button...
>>  I do not think it is a harddrive/os issue as when i press the button i get absolutely no feedback from the monitor and the computer refuses to POST or even get to the bios screen. I  <<     imo  - you assume way too much here
disconnect all devices, disk and cd drives - use the minimum setup as described in my aarticle to troubleshoot : https://www.experts-exchange.com/Hardware/Components/Motherboards/A_1945.html                  (Short-overview-of-how-to-troubleshoot-bad-hardware-when-a-pc-does-not-post)
disconnecting everything didnt seem to fix the issue yet. I read your article though, well written. It recommended taking it out of the case, can the case cause issues? Full disclosure, i didnt put in all of the motherboard screws as a couple were hard to get to and i didnt think it mattered. Does that cause issues?
first sorry for not reading question well ...seems  you had changed almost everything so PSU and capasitor options are down.

Two things left ;

Case - your power button may be in short circuit try building a test platform out of case with all necessary parts.

HDD - try installing a new os to a new HDD -even just for testing-

Along with these also there may be rom virus at the back of these which is alson in the bootsector of HDD , the option HDD will also may solve this too.

Good luck
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nobus
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If you have to do something out of the ordinary with the power to get it to boot, that seems to me that you have a faulty power supply, even though it's new.  There's also the possibility that your house power has developed a problem from the outage that is killing electronics, and every new power supply is affected by it.
power virus?
the power virus is starting to sound more likely. I just tried using 2 other computers in the house that previously i hadnt messed with since i was so focused on the server. Both of them are doing the same thing! How do i test the outlets? Is it even possible to be the outlets when other appliances and such work?
Electronics are more sensitive than appliances to out-of-range power.  To test the house, an electrician is recommended, though you can do simple voltage tests with a multimeter to get a ballpark idea if something is wrong.  In addition to voltage, improper phase and grounding can affect equipment.

http://www.thecircuitdetective.com/test.htm
yes, it looks like problems with the AC ...check it, or have it checked by an electrician
This seemed to have been the issue, i added the mounting hardware and it seems to work now. I guess perhaps the motherboard was shorting out on the case somehow? either way, works now. thanks!
tx for feedback
What about the other computers that were playing up? Are they working normally now?
One if them I assume died, but it was very old and I didn't spend much time on it. The other one and this is embarrassing...had a magnetic nut stuck to the bottom if the mother board I discovered after taking it apart at work when I brought it in to see if it was my apartments power.