CPU trouble LED on Asus Crosshair IV Formula motherboard

bobham

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Sep 11, 2014
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Hi:
I have a system I put together about 4 years ago based on an Asus Crosshair IV Formula motherboard using an AMD Phenom II X6 1090T Black edition CPU. I originally had 2 PowerColor Radeon HD5850 graphics cards running in Crossfire. I don't remember why now, but after a year or so I removed the HD5850 cards and installed a single Gigabyte Radeon HD6950. The system has been working fine since then.

On Thursday morning when I turned the system on the case fans started and everything seemed normal except there was nothing showing on the monitor during or after boot. I tried re-starting a couple of times but nothing changed. I dug one of the old HD5850 cards out and swapped it for the HD6950, and then the system booted normally and everything seemed fine. Based on that I assumed the HD6950 was toast and disposed of it. I also ordered a new R9 270 card which has been shipped but I have not received it yet.

The computer worked fine for the rest of Thursday and started and ran fine all day yesterday. However, the same problem occurred when I started the system up this morning. I tried swapping to the other HD5850 card I had but still have no display on the monitor. I connected the monitor to another computer and it worked fine on that one.

I do have an LED light on the motherboard near the 24 pin socket. I noticed it when I had the case open on Thursday but since the system seemed to be working fine I didn't look at it too closely and I also don't remember if it is new or if it has always been on. I took a look through the motherboard manual and it says the 4 LEDs near the 24 pin socket are "POST State LEDs". The manual says that these LEDs check key components during POST. If an error is found the LED will remain on until the problem is resolved. The one that is lit on my motherboard is for the CPU.

Is there anything I can do to confirm a CPU problem without having a display to show me what is happening? As I said, I can't remember if this light has always been on or not, but I do know that it was on for the two days the computer seemed to be working fine after swapping video cards. How likely is it that this is the problem with the display?

Thanks for any suggestions
Bob
 

8350rocks

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Do you have another CPU to test on that board?

EDIT: Your issue is, when it comes to CPU. The only way to test is to test the board and CPU separately to determine the issue. I ran into a similar issue in a fresh build a while back and had to test the components separately and ultimately determined the MB was the culprit and I RMA'ed the board for a new one. If you have no spare parts, then it may be tough to actually single out the problem entirely.

You could upgrade MB and CPU and it would certainly solve your issues. Though I wish there was a better solution, honestly...
 

bobham

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Sep 11, 2014
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All right, thank you. I don't have spare parts so I guess I will be starting over. I was just concerned the LED might be a red herring since I am sure it has been on for the past two days while the computer seemed to work fine.

Thanks again
Bob
 

8350rocks

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Well, the issue lies in the fact that your hardware could have some component failing...

That would explain the on again/off again issue.

The easiest thing would be to just go new. However, if that is out of your plans at this time, you might see if a friend has a component you can use to test.
 

bobham

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Sep 11, 2014
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Okay, thanks. I was hoping to put off re-building for a year or so but I don't have the technical savvy to diagnose problems like this. I can plug things in but that's about it. :)

Take care and thanks again
Bob
 

8350rocks

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One last thing, make sure to check all your power connections, etc. to all your components. If one of those has worked loose somewhere along the way, it could be the culprit. (Just trying to eliminate potential areas of trouble...)