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Intel core i7 920 not powering up

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September 28, 2010 1:34:21 AM

Hello,
I had a power supply die a couple weeks ago. Just got a replacement and when I powered it up, the lights blinked, and then nothing. Just for grins I disconnected the CPU power and everything powered up and it appeared as though things worked. I was thinking bad CPU, but it would really bite if that is it.

Intel Core i7 920 DO
Silverstone ST1500 1500W power supply
ASROCK X58 extreme
12 Gb G.Skill memory

Thanks!
September 28, 2010 1:59:47 AM

There are not a 4 or 8 pins (yellow and black) that you forgot to plug on the board ? xD

You said a bad CPU... you have replaced it or ?

Any sound from the board?
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September 28, 2010 4:39:09 AM

Used the CPU power connector from the PSU - 8-pin. Wish I had enough money to have a spare CPU around.
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September 28, 2010 4:51:54 AM

Remove all but one stick of ram. Remove all but one video card.... Basically just have the bare min hooked up to get the machine to post. If it posts reset BIOS to defaults and take it from there.
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a c 172 à CPUs
September 28, 2010 3:13:12 PM

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence or long single beeps indicate a problem with the memory.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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October 1, 2010 12:07:46 AM

Thanks JSC! Great information. If only I had come here first!!!

Turns out the processor is ok. The Intel service center nearby kindly tested it on one of their boards! Just submitted a tech support request to ASROCK. Keeping my fingers crossed.
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a c 172 à CPUs
October 2, 2010 5:28:55 AM

CPU's are rarely bad out of the box.
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October 12, 2010 12:17:42 AM

Best answer selected by twhelchel.
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a b à CPUs
October 12, 2010 12:31:40 AM

This topic has been closed by Mousemonkey
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