I've tried everything, pc turns on and then shuts off, I'm stumped, please help

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hotzpacho

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Jun 4, 2012
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Okay this situation is making me crazy. I have a computer from a friend who claimed to have purchased the parts and had someone else put it together. She claimed it worked then shut it down and it won't turn back on.

After inspecting the pc the motherboard was not indicating any power to it prior to turning it on. Once i pushed the on button the mb would light up for a split second and then off. None of the fans would spin.

The parts were:
Intel i7 6700 quad core LGA 1151 3.4ghz skylake
MSI B150 Gaming M3 motherboard
Hyper 212 Evo CPU heatsink fan combo
NZKT 230 Case (possibly, the model number is not well seen)
G.Skill DDR 2400 Ripjaws V (2x8GB)
1TB Seagate HDD
MSI GTX970 Nvidia Gaming 4G video card
Corsair 600M partial modular PSU

I took it apart and noticed two problems.

Problem 1: she has RAM that wasn't compatible with the motherboard. The RAM was ddr4 2400 and the board only accepted ddr4 2133.

Problem 2: A few of the socket prongs on the motherboard for the cpu were bent.

I had her RMA the board and RAM and they were replaced with:

Motherboard = ASUS H170 Pro Gaming
RAM = G.Skill DDR4 2133 (4x8GB)

Here is what i did:

Process 1: Installed all components in case > turned on psu > MB lit up indicating it was receiving power > turned on PC from case pwr button > all fans spin for about 2 seconds then stop > board remains lit up.

Process 2: Considered something was shorting the board in the case > removed all the components from the case > placed everyone on a solid wood surface > connected all the components > turned on psu > board lights up > turn on power switch from case > all fans spin for 2 seconds then stop > board remains lit up.

Process 3: Cycled each RAM module one by one in each DIMM Slot on board > power on PSU > board lights up > turn on from case > all fans spin for 2 seconds then stops > board remains lit up.

Process 4: Remove Video Card > followed same procedure > same outcome

Process 5 : Remove case fans > followed same procedure > same outcome

Process 6: Remove HDD > followed same procedure > same outcome

Process 7 : Tested PSU with a PSU tester and all readings were in the normal range > attached PSU to components > same procedure > same outcome

Process 8 : Reset CMOS > same procedure > same outcome

I'm completely at a loss and have no idea what to test next. Can anyone please help with this problem?
 
tinynja98

tinynja98

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Jan 17, 2015
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Try disconnecting the cpu fan but keeping it installed, and plugging a case fan into the cpu fan header on the motherboard and see if this works. I don't really know how much heat the i7 6700 puts out, but i would say if the system boots, don't go over 1-2 minutes. If this solves the issue, then there is probably a problem with the CPU fan.
 
smorizio

smorizio

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Jan 22, 2010
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i few things...one intel new cpu can run with any speed ram the intel default speed is 2100..2400 ram is fine in any new intel mb. 3000 speed ram has slower speeds in it eprom...not intel you turn on intel xmp profile will faster ram run at any speed faster then 2100. 2. the cx power supply are bad bad units with high failure rates. try pulling the gpu see if the onboard video and one ram stick come on. if not use another test power supply. if the mb wont post with the new test power supply. the cpu may have been fried from the bent pins. or the dead short from a bad fan or part. last trick is putting the mb on top of the mb box with one ram stick and cpu cooler see if it posts.
 
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hotzpacho

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Jun 4, 2012
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ive got the board sitting on cardboard flat on an all wood table. I don't have a spare PSU to test with or i would have tried that to begin with. I've tested each process with and without the gpu. i'm glad you did point out that the cpu could have been fried due to the previous board. does this sound more like a cpu or a psu problem in your opinion?
 
T

tsnor

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Nov 20, 2008
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Make sure the 4/8 pin power connector is plugged into the MB. This sounds like the 24 pin is in, but the 4 pin is missed.

Then read the "no boot, no video" sticky. It will tell you to pull parts until you get a post code, then to add in parts until you know the last part you add before the systme dies. That's usually the bad part.
 
panathas

panathas

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Feb 12, 2014
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I think you have a bad PSU there. PSU testers aren't reliable because they don't put a load or stress the power supply. Also this specific PSU has a very bad reputation. If your CPU was indeed fried, the system wouldn't turn on, or if it did, it would't be able to post, it would just freeze and sit there. The fact that it turns off, means that something with your PSU is wrong, and some protection mechanism shuts it down.
 
H

hotzpacho

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Jun 4, 2012
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okay two questions:

1. Even if the mb is lighting up the psu can still be faulty?

2. What is the best way to test the psu load without using a psu tester?
 
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junkeymonkey

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Nov 11, 2013
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well if it fires up and runs then call it a bad power switch if no change and still turns on and off ?? maybe a faulty psu as said above ?

I had a case with a bad switch that would act like this like it was like stuck between on and off ? its something known to happen and just thought I'd suggest that to try


''2. What is the best way to test the psu load without using a psu tester? ''

it maybe easier to get another psu to test the system with [borrow one ] I'd think something to do that dont comes cheap when you need it just for one time use like a review site would use like Johnny guru
 
panathas

panathas

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Feb 12, 2014
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Yes the PSU could be faulty even if it lights up the mb. The only way to be absolutely certain that you have a bad PSU, is to try another one in its place, or try to use this PSU on another similar system and see if it can power it properly without shutting down. Personally I would't recommend the second option because if you have indeed a bad PSU, it could damage the other system.
 
H

hotzpacho

Honorable
Jun 4, 2012
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how likely could the cpu be damaged by a bad board? From what i understand it seems more likely for the psu to go before the cpu. is that correct?
 
panathas

panathas

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Feb 12, 2014
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It depends. A bad board or a bad PSU could damage the CPU but it is very rare because there are protection mechanisms that protect the CPU. That's why motherboards and PSUs die more easily than CPUs. Also a motherboard or a PSU has a lot of electronic components and if one of them malfunctions then you have a problematic board or PSU. Also as I told you earlier, a fried CPU usually doesn't turn the system on.

In general when a system has this behaviour it's a bad motherboard or a bad PSU, and since you have a new board your PSU is most likely bad. But before you RMA it you need to try another PSU just to be 100% certain that it's the PSU that's bad and not the CPU.
 
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