Computers power up for 4 seconds then turns off

Zynpol

Honorable
Dec 21, 2012
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10,510
I have recently bought this PC:
Msi z77a-g43
Zalman z9 plus
I5 3470
Radeon hd 7870
Xfx pro 550w
8gb corsair vengeance
Stock hsf
1tb hdd sea gate barracuda


Did an external build - boot worked
Internal build worked
All stand offs are in

When i put the side panels on and start it up the computer starts, fans start and the hsf starts and all the front panel led starts
Then after around 4 seconds it turns off
I removed the side panels and its still doing it


Can anyone help me? Spent a lot of time at this desk building this pc
 
Assuming all is correctly connected, and considering you were successfully booting on "the bench", I would look toward a short (arcing) of a cable or stand off. Start pulling hardware out and eliminating pieces. Good luck and keep plugging away... These problems are a pain!
 
Does the fact that it started happening when the only change was putting the side panels on over the wires then it continues after removing the panel have anything to do within or point more specifically to something
 
That issue is consistent with a shorted power switch. Disconnect the power switch wires, and see if momentarily shorting those pins turns your PC on normally. If so, trace back the switch wires and/or test the switch.
This reminds me of the single Apevia case I bought some years ago. Some factory drone put a screw through the power switch wires. That and other quality issues earned that case a one-way trip to the grabbage after a few months of frustration.
 
yea. try removing the video card and boot with the onboard graphics. if that doesn't work i would reseat all cables and last resort pull it apart and retest on the bench then reassemble. clearing the cmos wouldn't hurt either.
 



Shorting the pw switch doesn't work, it turns it on then turns back off
 

Yes, movement of the power switch wires might have pulled exposed wires together, while removing the panel again might not necessarily have separated the short.
 
If you disconnected the switch wires, but the machine still turns off, check on and under the mobo for any foreign [metal] object like an extra screw. You say "all standoffs are in;" are there any where there is NOT a mounting hole in the mobo? If so, remove that one before something dies.
 


I need a break and to shower and eat haha

Afterwards I'm going to unplug everything, take the motherboard out and check anything that could touch the motherboard then after that one by one install in the case testing power each time, hopefully ill find out what it is

Thanks for suggestions everyone
 
Guys I have built it outside of the box with:

CPU
GPU
RAM


It is still doing it, there is also a screw stuck in a stand off

What now?
 
A screw stuck in a standoff? How so, did the mobo crack around it, or was the screw in place in the standoff located somewhere under the mobo? If the former, the mobo is almost certainly dead. If the latter, remove the standoff, but it may have already shorted something. Disconnect the power switch wires and use a screwdriver to make momentary contact between the pins. Does it power on? Does it shut off? Recheck your manual to make sure you're using the right pins. My own eyes are bad enough that I always need to recheck those.