Question Computer won't post at my house but does elsewhere and with CPU power disconnected

chrisgomm

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Right. This has me completely stumped. Firstly some context:

  • This computer has been working for 5 years. In that time i have replaced the PSU and CPU fan (less than 3 years ago). Otherwise, i have never had any issues.
  • The computer has been working fine without any issues until the past week when it was unable to be switched back on (it switched off over-night at some point)
  • When i start the computer (with either the button on the motherboard or the case), a red light comes on near the 24 pin connector called JPW01. OK, so it's a power issue.
  • However, here's the odd part:
    • When i take out the CPU power it starts fine
    • When i took it to the repair shop it started fine without any changes - just straight up worked after i brought it in, even witht he CPU power connected
  • I've narrowed it down to the motherboard failing (i hope not, i don't think they make them anymore in Aus/NZ), CPU fan failing, CPU failing OR (what i suspect) power quality issues in the house. However, everything else works fine in the house...
  • I've tried on different sockets and have the same issues throughout the house regardless of the circuit i am on. I've even tripped the mains breaker for a minute and flicked it back on to see if that would fix the issues.
I have searched online and have not found someone with the same series of oddities. The fact it works elsewhere tells me it must be something to do with power or how the computer is delivering the power to the components, but why it works here with the CPU disconnected confuses me! Could there be some checks the motherboard does that are failing (poor quality power?) that when i'm in another house it passes as the power is better quality OR because i'm disconnecting the CPU it doesn't do those checks and is able to start in my house?

Has anyone had this happen before and have any ideas how to resolve? Do you think a UPS may be a good next step to debug if it is the house's power quality or grounding? Or could this be a sign of motherboard failure or grounding of the case (which was knocked when travelling to the shop?).

Really appreciate the help, i imagine this may help others who may face a similar thing in the future!

Specs:
MSI X99S SSLI motherboard
i7 5820
16GB DDR4
Corsair 750M
Corsair H100i
R9 Fury
 

Ralston18

Titan
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What do you mean by:

"why it works here with the CPU disconnected "

and
  • When i take out the CPU power it starts fine
  • When i took it to the repair shop it started fine without any changes - just straight up worked after i brought it in, even witht he CPU power connected
What you posted does not fit "CPU"....

Do you mean a UPS, a power strip, some sort of surge protection?

What exactly are you doing: connecting and disconnecting?

= = = =

Also: double check the motherboard.

I looked for the applicable User Guide/Manual and the results were a bit confusing.

MSI Reference:

https://us.msi.com/Motherboard/support/X99S-SLI-PLUS#down-manual

For example:

Starting on physically numbered Page 1-8, I cannot find a connector labeled "JPW01"

There is a JPWR1 labeled 24 pin connector but no nearby LEDs that I can note.

If possible, take a couple of photos showing the motherboard and what you are working on.

Post here using imgur (www.imgur.com).
 

chrisgomm

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Thanks mate. Let me upload those pictures later when i'm home. Yes, apologies JPWR1 - the R looked like a 0. There is an LED there - although yes, not mentioned in the manual. But there are posts online about this motherboard and this light and i can certainly see one!

The computer starts in my house only if i unplug the CPU Power at the top of the motherboard. The computer starts elsewhere when i have it connected (it boots fine with no issues at the computer repair shop). Otherwise, there is a red LED by JPWR1 (i'll upload a picture later).

By UPS i'm referring to something like this: https://www.jaycar.co.nz/1500va-900w-230vac-lcd-line-interactive-ups-with-usb/p/MP5207 whose line interactive protection may flatten out the power (if it's a power issue with the house). I don't have one yet but wondering if this may ease the power issues if it is something to do with the power in the house.

What exactly am i doing - just trying to turn the computer on. The other details outline the debugging steps i've taken and some oddities in what fixes the issues i'm having to try to narrow down where the issue may be.
 

Paperdoc

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What you describe MAY not be the location of the system. It MIGHT just be an intermittent problem in a weaker part. Or, as you hinted, a poor connection that can be jostled. Years ago I had a vaguely similar problem - my system would not boot up unless I disconnected the power plug from the wall (OR turned off the power switch on the back of the PSU) for several minutes, then restored power. Over the space of months it progressed to worse, and ultimately was solved completely by replacing the PSU. I'm not saying that is your problem (could be) but just illustrating that intermittent issues can be tough to narrow down quickly.
 

rickypicky5

Commendable
The computer starts in my house only if i unplug the CPU Power at the top of the motherboard. The computer starts elsewhere when i have it connected (it boots fine with no issues at the computer repair shop). Otherwise, there is a red LED by JPWR1 (i'll upload a picture later).
Your computer cannot possibly "start" if you unplug the CPU Power. What do you mean by "start"? To me, "start" means it either boots to Windows, which, as far as I know, isn't possible without the CPU Power plugged int.
 

rickypicky5

Commendable
Hmmm. I want to make sure I understand this. His motherboard has a single 8-pin CPU power connector near the CPU. It doesn't have another 4/6/8-pin CPU power connector next to it, as some motherboards have, just the single 8-pin CPU power. I thought that if a motherboard has just one CPU power connector, it had to be connected to the PSU for the PC to work. If the motherboard has two CPU power connectors, the second one was typically used for 'extreme overclocking', and did not need to be connected for normal operation. Is this not true? I'm not trying to be argumentative, I'm just trying to understand.
 

thenewnumber2

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I would check the 12V supply voltage with meter when the light is on.
It should be between 11.4V and 12.6V
It would't hurt to check the voltage on the CPU power connector as well. If it's supplying a dirty signal to the CPU, that could explain why your rig only works when that connector is unplugged.
 

chrisgomm

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To clarify, it starts up, hard drives whir, motherboard lights signify that it is on and the red light isn't triggered with the CPU disconnected. It won't boot obviously as there is no processor to process. But it does allow the board to start signalling that its unlikely a problem with the other components.

I'll check the PSU voltage now with my multimeter and will share results when I can!

As well as checking the PSU alone. Is there a way to test the motherboard for power quality? Could be that the motherboard is on its way out and would be good to check if that's the case as well.

Thanks
 
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chrisgomm

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PSU Test:
  • All of the positive pins for the CPU power are showing 12v DC as expected.
  • 232 volts AC is being supplied to the PSU from the socket.
  • Just tested the 24 pin too. The only one that was close to the max tolerance was pin 14 which is -11V and not -12V, but even this is within 10% so should be fine...
Might this be a motherboard issue? Is there a way to diagnose the motherboard power?
 
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chrisgomm

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Ok, so it just booted after breadboarding. I assume the issue is with the grounding in the case. I'll put back together and see if it works in the case. If so, consider this oddity closed - most likely it worked in the shop due to movement whilst travelling that resolved the grounding issue.

Thanks to all that assisted me. Note for others with similar problems, check for grounding issues. It'll could be a power issue!
 

chrisgomm

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Back to it. I actually plugged my computer up to my monitor and now i don't get any signal from the graphics card.. Starting to think this might be a motherboard issue.

I'd love to be able to test to see if it is the graphics card, but unfortunately i have no integrated graphics on this motherboard so i can't boot to check.

Interestingly, the computer starts, everything gets power (CPU fan is whirring, board lights up with blue lights, hard drives whirr, graphics card's fans are spinning.). But no signal out of the graphics card. I've tried HDMI and DP. Bothe the same. I've also tried 2 different monitors so i don't think that's the case.

I want to try to use a different PCIE slot but i can't fit my graphics card into it (hard drives get in the way). I'll try to move that and check later, but for now i have an unusual situation!

Final note: When i power up, my monitor turns on from hibernating (assuming this means it has a signal from the GPU to trigger it to start), but it then says "no signal received, entering hibernation". Does this mean that we get a short signal when we first power up and then lose connection?

Also, when i plug in my mouse, it gets power as the mouse starts charging (wireless) but the keyboard does not. I click numlock and the light doesn't show on the keyboard - assume this means it is either not getting power or the computer is unable to interact with it (i've tried different ports and all the same result)

Are there any debugging tips that i can try?
 
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hedwar2011

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  1. This really sounds like something is grounding out the motherboard whether it be that it's touching another metal part, a grounding peg has rubbed somehow and is tripping it, etc. Each time you moved it it likely moved it enough to power on and off correctly like it should have.
  2. Make sure that your GPU is properly seated and not touching anything. Make sure the 12v rail is only going from the GPU from the power-supply and not touching anything else, if you can. I actually zip-tied mine to itself to reduce overhang and avoid drawbacks like this from happening. If your monitor is in hibernation and then comes on briefly it's getting the wake instance from the PC itself but when it realizes that there's no signal coming from the GPU it goes back to hibernation causing the message you're getting. When you tried it on both HDMI and DP did your monitor auto-adjust to match the connection? Ensure it did.
 

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