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Very Puzzling problem CPU/Mobo or something else?

Last response: in Components
a b à CPUs
January 29, 2013 7:30:04 PM

It's been a while since I have visited this site, but I have a puzzling problem that I absolutely can not figure out. I built a brand new system, below are the specs:

AMD FX 4100 3.6
MOBO AMD 970 pro
GSkill Ripsaw DDR 3 12800 1.5v
Seagate Baracuda HD 7200 SATA
DVD RW drive, salvaged from old HP with PATA-SATA board

PS had faulty Raidmax 530s
now has OCZ ModX pro 700w

And Im thinking a culprit to my problems may be this:
Nvidia 7950GX2

Anyway let me explain what happened. I built this system five months ago for a customer. When it was finished everything worked great, no problems. Then the customer didn't come to get the system for 3 months so I took the MOBO, CPU and Ram and stuck it in my computer and used it. Everything worked great. 2 months later the customers call me and ask if they can get the computer. Fine :fou:  . So I place everything back in the case and power it on, noting happens but I smell burnt electronics in the case emanating from the raidmax PSU.

So I cursed, spit and then removed the MOBO, CPU and Ram put it back in my system to see if the crappy PSU had messed things up. Yep, sure enough the fans spin, but no post, no beeps, CPU is dead. :pfff: 
So I bite the bullet and order a new CPU. It comes and I put it in the MOBO, bam everything works like new again. Five minutes later I smell smoke and then poof, no more processor. Some cussing and spitting and throwing a tantrum and then I RMA the CPU.

So now I have a new MOBO and CPU incoming, because I think the MOBO must also be damaged since it burned up that new processor.

My question is this, could the bad power supply have ruined circuits in more than the MOBO and CPU? And Why did the MOBO work for 5 minutes like normal before cooking the CPU? Don't they have safety features that protect these components?

The 7950GX2 is old, obviously and came out of a system with LOTS of problems, bad HD's, bad CPU, Faulty PSU. Could it be causing a short that could affect the processor and or motherboard?

Thanks in Advance, sorry for the long explanation but I want to be thorough.
a b à CPUs
January 29, 2013 7:50:14 PM

They do have safety features but unfortunately, the most important ones are located at the PSU itself, and Raidmax PSU's are notorious for exploding and taking other components with them. It could have damaged the MOBO and CPU in one swoop, and the damaged component may not have been active or under use until certain conditions are met, at which point it hits a fried contact or something and roasts whatever is connected. Moral of all these stories is do not skimp on the PSU unfortunately lol.
a b à CPUs
January 29, 2013 8:13:40 PM

Thanks for the Reply, I have learned my lesson on discount PSU's.

A question I have been pondering for a while is whether the GC, RAM or any other component could cause a short that would fry a Processor? I would hate to get a new CPU and MOBO only to have the system burn out again.

I have tested the HD and it has no problems, hasn't blown up the test bench yet. But I am afraid to test the 7950GX2 since it is a power hog and it's so old. Could it cause a problem? Or do you think this is a 12v issue on the MOBO only.
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a b à CPUs
February 1, 2013 10:47:04 PM

Update, new processor came. Placed it in new motherboard. No post, fans spin full speed, power button does not respond, I have to use power supply switch to turn off the computer.

I switched the GPU before testing, tested the HD in another computer before installing it. If the ram was bad I would assume I would see something or the power button would at least respond but nothing. Is this another bad MOBO or CPU?
a b à CPUs
February 4, 2013 9:27:17 PM

Problem Fixed: :bounce: 
I decided to come back and let everyone know what the solution to my vexing problem was.

It was a standoff in the new case from my mini ATX motherboard. It was touching the motherboard and causing a short. After removing this offset the system booted normally.

I am still concerned about the previous components, so I removed the 7900gx2 in favor of an old 9800gx2 that I had sitting around. I also removed the CD-DVD drive fearing the Parallel to Sata card may have issues as well.

So far everything seems great.

New system:
AMD 4100 Black
8gb GSkill Ripsaw DDR 3 12800 1.5v
ASROCK 970 pro
700 watt OCZ Mod X pro
Seagate Baracuda HD 7200 SATA
Some Generic Antec Design case with a bunch of fans.