Solved PC won't boot after CPU upgrade

June 30, 2017 at 00:45:43
Specs: Windows 10, x64, i5-6600/i7-7700
Hi all, today I upgraded from my i5-6600 CPU to an i-7 7700, I removed the old CPU fan, removed the old CPU, then I applied thermal paste to the new CPU coolers base, put the new CPU in (it fit) and put in the new fan. Then I tried to start it up, but it wouldn't boot, the fan spins but after about 20 seconds it shuts off suddenly, all with absolutely no picture on the screen, then I put my old CPU and fan back, and there was no change, it still wouldn't boot, except this time, the fan wouldn't spin either, I am incredibly worried, please help

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✔ Best Answer
June 30, 2017 at 10:11:26
Do not remove the motherboard. If it was working prior to the upgrade, there's likely nothing wrong with it.

"I applied thermal paste to the new CPU coolers base"
"The cooler came with thermal paste attached to it but I Still added a little extra"

Paste is supposed to be applied to the CPU, not the "coolers base" (other than factory applied). And if there was a pre-applied pad or paste, you should NOT have added more paste to it.

Reinstall the i5. Make sure to thoroughly clean ALL traces of the old thermal material from both the CPU & bottom of the heatsink. Apply fresh paste on the CPU using the vertical line method, then install the heatsink/fan (aka cooler).

http://forum.corsair.com/v3/attachm...

If the system boots up after doing the above, update the BIOS to version F21. After that's been done, swap the i5 for the i7, repeating the thermal paste application process. Do NOT re-use the old paste.

message edited by riider



#1
June 30, 2017 at 01:05:50
What is the make model of your motherboard and PSU?

When removing the CPU did you disconnect the power lead? it is advisable to remove the power lead from the back of the PC and hold down the power button for 10 seconds to discharge all the capacitors.

Are you sure you didn't accidently pull any of the other wires out? CPU power cable, 20/24 pin motherboard cable etc?

double check all connections, if they all look good, it may be worth pulling the board out and bench testing it with

1 stick of ram
Onboard graphics first, then with you GPU

test the PSU if you can with a voltmeter too.


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#2
June 30, 2017 at 01:15:50
Thanks for the advice, I switched the power off at the wall and at the cable when I changed CPU's, I did check all of the connections, but I might have missed one so I'll do that again, would it be possible that it's something to do with the thermal paste? The cooler came with thermal paste attached to it but I Still added a little extra to be sure, I made sure that it didn't go anywhere that is not the CPU. The motherboard is a gigabyte GA h170 Hd3, the PSU is a corsair 600W unit

message edited by aidanw2000


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#3
June 30, 2017 at 01:43:09
With thermal paste there is a lot of debate on whether to use the stuff that comes reapplied or to use something like Arctic MX 4 or Artic Silver 5.

Personally remove all the pre applied stuff and use Artic MX 4. There is also debates about using too much or too little, it is best not to add any more on top of what was already there, having said that it should not really affect the way the PC boots, IE you should at least get some video, even if you applied it incorrectly and it overheated, you should see something on the screen.

The PSU is from a known good brand, however that doesn't mean that it may not have failed, would be worth testing it with a volt meter.

My guess would be that either the PSU is shot or you have a loose connection, perhaps even something shorting out the board. Maybe your dropped something, a screw, behind it, no idea.

At this point I would be removing the board and testing outside of the case to

1) Avoid further damage
2) To be able to rule out components
3) give you a chance to clean things as well

It doesn't take much time so is my recommendation, see what others say, but my guess is that they will perhaps suggest the same thing, remove the board and bench test outside of the case.


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Related Solutions

#4
June 30, 2017 at 03:00:32
What version is your BIOS? It needs to be F20 or F21 to support that processor.

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#5
June 30, 2017 at 03:11:22
Yeah, I figured that, but it still doesn't work when I switch back to the old CPU

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#6
June 30, 2017 at 03:13:58
aidanw2000, hence why I am suggesting removing the MOBO, have you checked the seating of all cards, ram etc? made sure all cables and plugged in an tight? if so then my previous suggestion would stand.

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#7
June 30, 2017 at 03:19:01
Yeah, I plan to do that as soon as I get home

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#8
June 30, 2017 at 03:21:00
My plan of action when I get back is: 1. Re apply thermal paste, 2. Check all seatings and connections again, 3. Restart with only one stick of RAM, 4. Test the motherboard outside the case.

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#9
June 30, 2017 at 03:36:37
5) if you have a voltmeter check PSU voltages.

If you decide to do this, here is how you can do it.

With the PSU out of the case

1) locate the 20/24 pin connector, using a paper clip or a piece of wire connect/short the green wire (PS ON) to any of the black wires (GROUND).

This will switch the PSU on when you plug it into the mains.

Now with the voltmeter set to voltage

Probe the Yellow wire (positive) to a black wire (ground) - this should give you aprox 12v give or take
Probe the Red wire (positive) to a black and this should give you aprox 5v
Probe orange to black and should give you aprox 3.3v

Please tell us what readings you get from each rail.


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#10
June 30, 2017 at 05:03:06
Unfortunately I do not have a voltmeter, I just checked my garage, however, I have removed all except one stick of ram and reapplied the thermal paste and now the PC runs without shutting down, but the screen still remains blank, the lg logo shows, then it just says power saving mode and the screen switches off

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#11
June 30, 2017 at 10:11:26
✔ Best Answer
Do not remove the motherboard. If it was working prior to the upgrade, there's likely nothing wrong with it.

"I applied thermal paste to the new CPU coolers base"
"The cooler came with thermal paste attached to it but I Still added a little extra"

Paste is supposed to be applied to the CPU, not the "coolers base" (other than factory applied). And if there was a pre-applied pad or paste, you should NOT have added more paste to it.

Reinstall the i5. Make sure to thoroughly clean ALL traces of the old thermal material from both the CPU & bottom of the heatsink. Apply fresh paste on the CPU using the vertical line method, then install the heatsink/fan (aka cooler).

http://forum.corsair.com/v3/attachm...

If the system boots up after doing the above, update the BIOS to version F21. After that's been done, swap the i5 for the i7, repeating the thermal paste application process. Do NOT re-use the old paste.

message edited by riider


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