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New Build: Won't Post, no fans running

B

beginner99

Diamond Member
I've built a few PC's but now is the first time I'm having an issue ever. I have everything connected:

24 Pin and 8 pin motherboard power, CPU and RAM, harddisks. Also the power button cable. But when I press the power button nothing happens. No fans spin, nothing.

Powersuply is turned on and wall outlet has power. I also cleared CMOS according to MB's manual.

What are the recommended steps for trouble shooting?

EDIT:

2 case fans start to spin for a fraction of a second when I press the power button but then stop again. CPU fan does not spin at all. If I press power button again nothing happens. If I clear CMOS then the 2 case fans start to spin again but instantly stop like power is lost.
 
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Are you sure the switch is in the on position? Almost sounds like it was in the on position (so it had some 'charge') and when you pressed the power button the power discharged (seen visibly by brief board lights and fans spinning).

If not that, do you have a spare PSU sitting around?
 
Check all your power connections. It's possible one is not entirely seated.

Other trouble-shooting steps:
(1) remove all but one stick of RAM, placing it in second slot if there are four slots, or first slot if there are two.
(2) remove separate video card if you have one installed.
(3) unplug all hard drives.

A spare power supply wouldn't hurt either, just to test things out - what is the model you have? My guess is that it is not the problem, though.
 
Ok, so you have a straight-forward build - it should be possible to figure this out.

I've had fans spin up like that when not all motherboard connectors are firmly locked in place. The fact that the CPU fan isn't spinning tells me that the fan headers aren't getting power. Is that 120mm rear fan on a molex connector or is it connected to a fan header? Any other fans in the case? Do they spin?

I also see you have a Seasonic power supply. The odds of the PSU being the issue are probably on the order of 300 to 1. I'd troubleshoot everything else before replacing the power supply.

Also, testing with no RAM is not equivalent to testing with one stick. No system will boot without RAM.
 
Did you install standoffs behind the motherboard? The symptoms you're getting are similar to those you get when the motherboard is shorted out. Try pulling the board out of the case and running it on a cardboard box to be sure.
 
mfenn said:
Did you install standoffs behind the motherboard? The symptoms you're getting are similar to those you get when the motherboard is shorted out. Try pulling the board out of the case and running it on a cardboard box to be sure.
Click to expand...

I was going to say the exact same thing. This should be your next troubleshooting step.
 
mfenn said:
Did you install standoffs behind the motherboard? The symptoms you're getting are similar to those you get when the motherboard is shorted out. Try pulling the board out of the case and running it on a cardboard box to be sure.
Click to expand...

I'll second this idea
 
mfenn said:
Did you install standoffs behind the motherboard? The symptoms you're getting are similar to those you get when the motherboard is shorted out. Try pulling the board out of the case and running it on a cardboard box to be sure.
Click to expand...

Standoffs are installed.
 
beginner99 said:
Standoffs are installed.
Click to expand...

I would still remove the motherboard and try to run it sitting on a cardboard box. Just the motherboard, CPU, CPU cooler, power connections and one stick of RAM. Not even a video card, just see if you get signs of a POST - spinning fans, green lights on MB, etc.

If that doesn't work, try it without even hooking up the computer's power switch - use the tip of a screwdriver to momentarily short the PWR pins together.

Even with standoffs installed it's possible to have the motherboard short out. On my first build I had a screw fall behind the motherboard and it was sitting in just the right spot to hit a contact somewhere and cause a complete short that prevented the machine from even turning on.
 
I think it should be standard procedure to check new mobos out on the bench prior to installing in the case. This can save a lot of time in the long run.
 
OK. Was lucky. My intuition was right. The first component I disconnected was the culprit. The issue is the installed "front access panel" eg. card reader + USB and eSata ports. If I connect it to the power supply, the issue happens. If I do not connect it, everything works just fine. I'm writing this post from said new PC.

I'm going to return/RMA that card reader. I tried 2 different modular cables (molex) and 2 different modular ports on the PSU. The issue is def. caused by the card reader.
 
You have a card reader that connects to the power supply?

Most I've seen have a header that connects to the board, or to a port looped through the back.
 
Remove the motherboard from the case. Try shorting the power pins with the absolute minimum devices connected. That means no CD drive, no HDD, no video card installed. No usb devices. No usb devices. No monitor. No ethernet. No fans, excpet the cpu fan. Just two motherboard power connections from the power supply. Do this just to see if it turns on and stays running. If it does, then power down, connect a monitor and a keyboard and try again.
 
beginner99 said:
OK. Was lucky. My intuition was right. The first component I disconnected was the culprit. The issue is the installed "front access panel" eg. card reader + USB and eSata ports. If I connect it to the power supply, the issue happens. If I do not connect it, everything works just fine. I'm writing this post from said new PC.

I'm going to return/RMA that card reader. I tried 2 different modular cables (molex) and 2 different modular ports on the PSU. The issue is def. caused by the card reader.
Click to expand...

Wow, that is surprising. I've never heard of a simple component like that causing a failure to post.
 
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