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Two shorted CPUs - motherboard(s) or PSU issue?

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January 21, 2014 3:02:35 PM

As the title says, I've had some pretty bad luck with CPUs. I lost 2 CPUs in my setup before finally switching to a laptop while I wait for them to be replaced.

Specs:
Gigabyte 990fx UD3
OCZ 700W PSU
AMD 8150
7870 GHz Edition
8gb G. Skill x2
2gb G. Skill x2

*I upgraded from an ASUS 970x and had no issues with any of the parts prior to the Gigabyte board upgrade.

Upon assembling the rig above I received no display, fans and HDD spun up.
I tried 6 different sticks of RAM one at a time, and 5 different video cards I had access to (Radeon and Nvidia).

RMA'd the gigabyte board.

2nd gigabyte board came in, same system specs - assembled the rig a little more cautiously
(anti static precautions, double checked mobo + CPU power, PCI 6x connectors, ect)

Same result - fans but no display.
I tried a second 8150 CPU I had access to, same thing - fans but no display.

I put both CPUs in the ASUS 970fx board I upgraded from and received an immediate red CPU light indicating faulty CPU or ram - fans & no display.
I tested the CPUs in 2 more boards to confirm they were broken.

Tested the ram to work
Tested the 700w psu to work in a separate rig


What gives? All the parts besides the Gigabyte boards worked previously. The 8150s were under waranty, I just received my first replacement, figured it would be safest to take to a forum about this puzzling issue before trying anything else.

Edit: There were a few occasions where I randomly received no fan, led, or HDD activity with these boards - however simply unplugging the computer and reseating connectors seemed to fix it.

Edit 2: In another test, I tried an AM3 CPU I confirmed as working in another computer.
Phenom II 555 gave the same results in the setup I'm diagnosing - fans and no display.
a c 380 à CPUs
a b V Motherboard
a b ) Power supply
January 21, 2014 3:10:13 PM

Did you use the brass dividers?
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January 21, 2014 3:19:49 PM

ewok93 said:
Did you use the brass dividers?


Yes, I used as many of the brass riser screws as I could to make sure it couldn't be the case shorting things out - even tried the Gigabyte boards on the box. I always end up with the same result
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January 21, 2014 3:23:55 PM

one of the power suply pins may be bent on the 4/6/24pin or doest handle the short burst of startup, cant you find another power supply to test?
or maybe a stuk reset buton
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January 22, 2014 6:30:24 AM

I haven't added any load to the PSU, just upgraded the motherboard.
The entire setup worked with the PSU prior to upgrading the board - startup burst wouldn't make sense.
Unfortunately getting another PSU to test will take some time.
The reset button wasn't connected - I tried it with and without, so it isn't that.
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a c 380 à CPUs
a b V Motherboard
a b ) Power supply
January 22, 2014 11:41:37 AM

Thermal paste on a pin maybe?
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January 25, 2014 5:08:33 PM

ewok93 said:
Thermal paste on a pin maybe?


I carefully examined the CPU pins to assure none were bent, would've seen thermal paste or any physical defects, the CPUs weren't the problem.
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a b V Motherboard
a b ) Power supply
January 25, 2014 6:12:57 PM

your motherboard page
http://www.gigabyte.com/products/product-page.aspx?pid=...

"To enable AM3+ AMD FX-Series CPU support, please update your motherboard with the most current BIOS found in your motherboard’s download section."

you have an am3+ fx cpu did you upgrade the bios? if not then that's the issue as its in red right near the top of the page
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January 26, 2014 4:45:23 AM

maxwellmelon said:

"To enable AM3+ AMD FX-Series CPU support, please update your motherboard with the most current BIOS found in your motherboard’s download section."


I've had to do this BIOS update on other AM3+ boards, not the issue here.
I failed to mention I tested a Phenom II from a fully working computer in my plethora of tests - same result, no display. I couldn't update the BIOS if I wanted to.

Even if it were the case, FX series CPUs and the AM3+ socket has been around for well over a year, all boards should have this update factory installed by now.
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a b à CPUs
a b V Motherboard
a b ) Power supply
January 30, 2014 6:34:20 PM

did it burn up the phenom II?

anyways what your saying comes down to two items if its burning up cpus.

bad power supply (just because it powers up another system doesn't mean voltages are in spec it could be the other motherboard has better filters in place to fix bad power supplied to it)
bad motherboard again(was it a new motherboard or did they just reship your 1st motherboard back to you that you shipped them)
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a c 106 V Motherboard
a b ) Power supply
February 11, 2014 8:59:13 PM

After reading your described problem, first thing that came to my mind is that your PSU has shorted power cable. You should try other PSU to confirm or rule this out.

Have you tried by just plugging in CPU, one RAM and then powering on the system while all other things unplugged or disconnected?
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