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New Sabertooth z77 mobo, new Core i5 - RED CPU LIGHT AGAIN!

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May 26, 2013 3:28:47 PM

I recently bought a brand new Asus Sabertooth z77 Motherboard and a new Core i5 processor. I couldn't get any video, and the CPU light was lit. There were no bent pins, fans were spinning, etc, so myself and a helpful Tom's Hardware member decided it was either a bad board or CPU. Sent both back and got new ones... And the SAME THING is happening again. The i5 is on the list of supported CPUs by Asus. I flashed the bios to the newest version - nada. I know my PSU is okay because it works fine with my old parts. All I am running is the mobo, CPU and heatsink, 1 stick of ram, and CPU, all on a piece of cardboard not in the case. I also checked both the 8 and 20 pin power connectors to make sure they were inserted correctly. No other error lights are lit except the CPU light. What am I missing?? D:

Thanks to anyone who can help!!
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May 26, 2013 4:11:57 PM

1. What PSU make model wattage?

2. Check for bent pins?

3. Try different slots for the RAM

Most of the time these problems are PSU related, there no way you could have received two bad boards and cpus in a row!
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May 26, 2013 4:48:00 PM

My friend had this exact problem, red CPU light and we spent 5 hours trying to figure it out.... He had the Z77 Sabertooth and an i7 2600k and it was all good. He upgraded to the 3770k and gave the 2600k to a mate as a bday present, we were building / upgrading 3 computers at the start of a LAN.

So the CPU light came on when we put the 3770k in, he was using an Antec Khuler 620. Swapped the 2600k back and it works... Put the 3770k in the friends Asrock Z77 and it works....

5 hours later I found something that said "IGNORE CPU FAN" and that fixed it! it seems that if you have an aftermarket heatsink, you need to ignore the this in the BIOS. I'm not sure of the exact setting, so forgive me. You will also need access to another 1155 CPU to drop in there. I also don't think it worked with the stock cooler now that I think of it, it must be an issue with that board and the 3770k / 3570k / Ivy.

Hope that helps.
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May 26, 2013 5:02:15 PM

If your using a heat sink with a metal back plate make sure your using the foam spacers. I dd this on my saber tooth I over tighten the CPU screws. The ib have weak top cases.to much down force on them can cause them to short out. Make sure ram dimm is locked in. Also check that the heat sink not shorting to any of the caps that are around the CPU lot.
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May 26, 2013 9:45:43 PM

Thanks for all the replies, guys!

redeemer said:
1. What PSU make model wattage?

2. Check for bent pins?

3. Try different slots for the RAM

Most of the time these problems are PSU related, there no way you could have received two bad boards and cpus in a row!

It's a CoolerMaster 650 Watt. It's always worked fine on my current mobo, which granted, is a Micro ATX Asus something or other. Draws much less power than this beast, I'm sure. I've tried different sticks and slots for ram, and there are definitely no bent pins. I agree that this is too weird for me to have gotten this problem twice! Makes me worry about my PSU, too, but I'm using it right now with my old parts and it's fine, and surely 650 Watts is enough for just a mobo, CPU, and RAM?

pezonator said:
My friend had this exact problem, red CPU light and we spent 5 hours trying to figure it out.... He had the Z77 Sabertooth and an i7 2600k and it was all good. He upgraded to the 3770k and gave the 2600k to a mate as a bday present, we were building / upgrading 3 computers at the start of a LAN.

So the CPU light came on when we put the 3770k in, he was using an Antec Khuler 620. Swapped the 2600k back and it works... Put the 3770k in the friends Asrock Z77 and it works....

5 hours later I found something that said "IGNORE CPU FAN" and that fixed it! it seems that if you have an aftermarket heatsink, you need to ignore the this in the BIOS. I'm not sure of the exact setting, so forgive me. You will also need access to another 1155 CPU to drop in there. I also don't think it worked with the stock cooler now that I think of it, it must be an issue with that board and the 3770k / 3570k / Ivy.

Hope that helps.

Unfortunately, I can't even get to the BIOS to change any settings. The CPU error is making it so I don't even post. Wish I had another CPU to drop in there, but the only one I have is the other bad one that I haven't sent back yet.

smorizio said:
If your using a heat sink with a metal back plate make sure your using the foam spacers. I dd this on my saber tooth I over tighten the CPU screws. The ib have weak top cases.to much down force on them can cause them to short out. Make sure ram dimm is locked in. Also check that the heat sink not shorting to any of the caps that are around the CPU lot.

I'm just using the stock Intel heatsink for now, before I go through the trouble of installing my good, big one. So, all plastic. No shorts.

Any more ideas? Thanks a lot!
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a c 190 à CPUs
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May 27, 2013 10:10:50 AM

The only other cause of the red CPU led to come on is the eight pin pci power plug on the edge of the mb is not connected or you plugged in the six plus two pin power cable for a video card. The asus mb will run with a four pin cable connected if your ps does not have eight pin cable. Also check your power supply see if it atx 1.0 spec or 2.0 or higher. Most new mb vendor make there mb work with atx 2.3 power supply's now.
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May 27, 2013 11:37:39 AM

It IS the power supply! Thank you to smorizio and redeemer for making me think about this! I was convinced it couldn't be the power supply, since it's worked fine on older parts. What's alarming is this PSU always has and still runs my current motherboard and cpu just fine, or at least, appears to. Should I be concerned about this?

The power supply is this model: http://www.tigerdirect.com/applications/SearchTools/ite...

I finally hooked up an old power supply from a decade old computer, and while I wouldn't trust it to run this beast of a motherboard for more than a few minutes, it made it to BIOS no problem. So clearly, something is wrong with my current PSU. I tried running the Sabertooth board with the current PSU using all 8 pins or just 4 pins. It will not post, throwing the red CPU light error. My old board is a micro atx asus, and only uses 4 pins. Just wondering if all I need to do is buy a new PSU for the Sabertooth, and can I still use the old Coolmax one on the old board, since I planned on putting that board into a media box? Or is this thing a hazard to my rig and should I get rid of it?

Thanks so much for helping me finally solve this issue.
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May 27, 2013 2:54:04 PM

Siesna said:
It IS the power supply! Thank you to smorizio and redeemer for making me think about this! I was convinced it couldn't be the power supply, since it's worked fine on older parts. What's alarming is this PSU always has and still runs my current motherboard and cpu just fine, or at least, appears to. Should I be concerned about this?

The power supply is this model: http://www.tigerdirect.com/applications/SearchTools/ite...

I finally hooked up an old power supply from a decade old computer, and while I wouldn't trust it to run this beast of a motherboard for more than a few minutes, it made it to BIOS no problem. So clearly, something is wrong with my current PSU. I tried running the Sabertooth board with the current PSU using all 8 pins or just 4 pins. It will not post, throwing the red CPU light error. My old board is a micro atx asus, and only uses 4 pins. Just wondering if all I need to do is buy a new PSU for the Sabertooth, and can I still use the old Coolmax one on the old board, since I planned on putting that board into a media box? Or is this thing a hazard to my rig and should I get rid of it?

Thanks so much for helping me finally solve this issue.


awesome
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a c 462 V Motherboard
May 27, 2013 7:08:53 PM

It one where the cheap power supply came back to get you. it could be a low 5v power good line. Or the power supply not really rated for 650w and under good load the 12v line is weak. Look into cosair or seasonic unit or rebranded seasonic unit.
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