PC won't start after installing CPU heatsink & fan

[Topper Harley]

I've just installed a Cooler Master Hyper 103 to replace my stock heat sink and fan and now my PC won't start. When I press the on button nothing happens at all. There is no light on motherboard.

My specs are:
Gigabyte Z87 D3HP motherboard
Intel i7 4770k @ 3.50ghz
16gb RAM (4x4gb sticks)
2GB 7200rpm hard disk
Nvidia GTX 980 ti
Cit 750w PSU

It worked fine before I installed the cooler master. The installation went without a hitch so I have no idea what's caused this. I carefully cleaned the old thermal paste off the CPU and applied new stuff before seating the heatsink.

As the cooler master requires a back plate to mount I had to take everything off the motherboard and unscrew it from the case in order to take it out and gain access to the back. Could moving the motherboard out of the case inadvertently damaged it?

I've looked at threads on similar topics and checked everything I've seen there-

Motherboard power is connected
12v CPU 4 pin power is connected
All lights for power button/hard disk/reset are connected in correct pins.

Anyone have an idea what could be wrong and how I can fix it?

 

[alexoiu]

Try testing the power supply: https://www.youtube.com/watch?v=5FWXgQSokF4
See if fan connected to it does spin. Make sure that the PSU switch is turned on.

 

[techgeek]

I know it sounds stupid, but I've got to put it out there. Does you PSU have a on/off switch on it? If so, is it in the on position?

I know this sounds kind of arrogant, but it's not meant that way. I've seen plenty of people more than capable with computers and troubleshooting tear there hair out over the simplest thing.

 

[Topper Harley]

Thanks for the suggestions
Yes the PSU switch is on and it does power on with the paper clip test so I guess that's the PSU ruled out as the problem.

 

[techgeek]

Have you tried to manually short the power switch pins on the front panel header pins? Just in case the case switch is bad.

 

[Topper Harley]

No I haven't Techgeek, how do I do that?

 

[techgeek]

No I haven't Techgeek, how do I do that?

The two pins that you have the power switch connected to, short those with anything conductive that is big enough to bridge between the two pins. A coin or screwdriver would work. I had a look at your motherboard manual and it doesn't appear that it has an onboard power switch, so the method I described will work. If it doesn't power up using this method, then it's not a problem with the power switch on your case.

Another thing you might try is to clear the CMOS via the jumper on the motherboard.

 

[Topper Harley]

It didn't power on after shorting the switch.
What exactly does clearing the CMOS do and how do I do it?

 

[techgeek]

It essentially sets the BIOS back to defaults. So if there were anything in there that was keeping your computer from POSTing, it would be cleared. It also forces the motherboard to update the DMI information. There is a jumper on the motherboard and called CLR_CMOS and it's located just above the front panel header. The process is detailed on page 25 of your motherboard manual.

However you can't rule out the PSU. Just because it will turn on disconnected from the motherboard doesn't mean that it will work connected. There is a signal that is sent to the motherboard call PWR Good. Essentially when the PSU detects that the power switch has been pushed, it turns on. When the PSU sees that all the rails are present, stable and at the correct levels, it sends a signal to the motherboard telling it it's safe to turn on. If the motherboard doesn't get this signal, it won't turn on.

 

[Topper Harley]

Thanks so much for taking the time to help, I appreciate it.
I found what the problem was, and it was just me being stupid

The power switch was plugged into the power LED pins on the motherboard, not to the power switch pins. Pretty dumb of me not to notice but at least it's working now

 

[techgeek]

Glad you got it sorted out. Sometimes it takes stepping back and then coming back to it.