New PC won't turn on - any advice appreciated!

[Rhys_H]

Hi guys,

Recently built a new PC (specs below). Constructed everything, and worked like a dream for a week before I left for an overseas trip. Upon my return, the PC wouldn't start up. I pulled the side panel of the case off and found that a resistor and capacitor on the motherboard had shorted off each other. I sent the motherboard back via RMA and just received my replacement motherboard today.

Installed everything AGAIN, and to my horror, the PC wouldn't start...again. So far I have:

• 
  – Isolated the PSU to see if it was the issue (the fan turned over fine) --> not sure if this is thorough enough to exclude the PSU.
  – I left it plugged in and powered for 10 minutes, searching again for shorts, but couldn't find anything.
  – Tried to alternate between 2, 1 and 0 RAM sticks inserted.
  – I pulled all wires from the motherboard and PSU, with only the motherboard, front power switch and CPU plugged in.
  – Pulled the CPU --> no bent pins, no scorch marks.
  – I've noticed that the ethernet port LEDs come on for ~2 seconds on the rear panel, and then turn off --> I don't know the significance of this though haha.
  – Tried a different PSU (650W from my previous computer) --> same effect as before...

Nothing has worked so far, and it's driving me nuts. The PSU emits a noise (varying from a high pitched noise to a quiet operational noise i.e. fan running) depending on what is plugged into it at the time. If I pull the additional 10-pin
motherboard connector out (I think it's part of the motherboard connector?), the CPU cooler fans (Noctua) and the case fans gyrate, but don't complete full revolutions.

• 
  CPU: Intel Core i5-6600K 3.5GHz Quad-Core Processor
  CPU Cooler: Noctua NH-D15
  Motherboard: ASRock Fatal1ty Z170 Gaming K4 ATX LGA1151 Motherboard
  Memory: G.Skill Ripjaws V Series 16GB (2 x 8GB) DDR4-2400 Memory
  Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive
  Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive
  Video Card: EVGA GeForce GTX 1070 8GB SC Gaming ACX 3.0 Video Card
  Power Supply: EVGA Supernova 750W G2

Does anyone have any ideas of what to try next? If all else fails, I think I'm going to have to bite the bullet and get it professionally tested. I'm able to provide any photos/videos that you may need!

Thanks in advance guys, this place and all of you are life-savers.

 

[AppleGwava]

i would say that the short blew more components,if you have spares,swap out components to test


more steps than a 100 story building here ,

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems


AppleGwava

 

[KalTorak]

Do you have a spare rig you can test any items in? Such as the gfx ram and powersupply?

If its was a short on the motherboard, I would expect the likely boot fails now are caused by 1 other or both of 2 things.

CPU
PSU.

 

[Rhys_H]

i would say that the short blew more components,if you have spares,swap out components to test


more steps than a 100 story building here ,

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems


AppleGwava

I have pulled everything out of the equation, and left only the CPU, motherboard and PSU connected. If the alternate PSU encountered the same issues, am I correct in assuming that the motherboard or CPU are at fault?

I just got the brand new motherboard today, so could it be the CPU despite it not displaying any visible damage (e.g. no blown resistors, scorch marks, etc.)?

 

[Rhys_H]

Do you have a spare rig you can test any items in? Such as the gfx ram and powersupply?

If its was a short on the motherboard, I would expect the likely boot fails now are caused by 1 other or both of 2 things.

CPU
PSU.

I have tried to boot with both the graphics card and RAM pulled out, but had no luck. I put an alternate PSU in, and still the same. I asked below, but could it be the CPU if it doesn't show any visible damage? I plucked it from the motherboard and I couldn't see any blown resistors or scorch marks...

 

[Rhys_H]

I just fiddled with some of the power connections for the case (located on the closed side behind the motherboard) for the umpteenth time, and it worked. I have no idea how this happened, but it worked.

Thank you so much for your guys, I feel like a right tit. I've fiddled with everything so many times, and got nowhere. No idea. I won't ask any further questions though 😉 I'll let it run for a bit and see if it holds up.

 

[KalTorak]

Hmm, odd that that would cause a problem, and also that your board shorted out last time.

Are you using the standoffs for the motherboard so it is boosted up away from the metalwork?

Anyway, good its all up and running!

 

[Rhys_H]

Hmm, odd that that would cause a problem, and also that your board shorted out last time.

Are you using the standoffs for the motherboard so it is boosted up away from the metalwork?

Anyway, good its all up and running!

Yeah it is odd, and I'm not sure if that's what caused the short last time. My case came with pre-installed motherboard elevation pillars, so I don't think that's the issue. We'll see what happens though, it very well may short again!