HELP! No POST, No Beep, Fans Spin?

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It is probably....

  • Bad PS

    Votes: 4 26.7%

  • Bad MB

    Votes: 7 46.7%

  • Bad CPU

    Votes: 0 0.0%

  • The cheese-wiz I used as thermal paste

    Votes: 4 26.7%
  • Total voters
    15
A

akfish

Distinguished
Jan 15, 2007
2
0
18,510
Last night I put my system into standby (didn't check to see if it entered it fine)... When I came back this morning, the green light on the front of the case was flashing like it was in standby, but all the fans were still spinning. No monitor display, no response from the system. I tried holding down the power button, and it would seem to shut off, but when I tried turning it back on, got no display and no hd activity. I turned off the machine using the power supply switch on the back, and unplugged it.

Now when I power on the system, all the fans spin, but that is it. No beeps, no display, and the green power light doesn't even come on. The motherboard's onboard power led lights up. If I remove the video card, there are still no beeps, so it isn't getting to POST.

Tried removing cmos battery & reseting the motherboard with the jumper, no effect.

I think it may be the motherboard, power supply, or (maybe) CPU. The computer was on a surge suppressor, and there are no other damaged computers or blinking microwaves to indicate a power outage. My southbridge fan sounds like it is definitely going out though; if the computer is on its side, it makes a horrible noise (which I didn't notice because I don't ever have it on its side!)

I always keep a close watch on my temps, even though my machine isn't overclocked, and I get around 38c load on my cpu & mb, 30c idle.

Asus a8n5x
AMD x2 3800 939
Coolermaster RealPower 450
eVGA 7900 GT
4x Corsair DDR 3200 Value memory

I do have another 939 PCI-E machine that I can use to swap out components, but if the PS is bad I don't want to ruin other components.

1) Has anyone had this kind of problem?
2) What is the "best" way to swap out components so I a) don't ruin anything else and b) can have a solid case to present when I ask for an RMA on whatever is bad?
3) Am I missing anything? Any other suggestions?
 
Sounds like a dead M/B. Borrow a power supply, unplug all your peripherals and see if it powers up. My experience has been, when the power supply blows it takes the HD, and sometimes the M/B. But then ususally nothing will power up -- fans, lights, nada. If it's memory or video, you usually get beep errors. Good luck.
 
Bad motherboard or CPU too. Verify they are working, borrow a motherboard and try the cpu, then use your cpu on other motherboard to make sure 😉
 
I had this problem and it turned out to be the CPU fried. I removed the CPU and took it to Comp USA and they confirmed it was toast. You could remove the CPU and power it up and see if you get the same response.
 
Somethings definitely fried. I think the power supply almost certainly gone, and the question remains, has anything else fried as well. Don't plug the psu into another computer. You need to get a psu from another computer and put it into yours to test and see if your m/b is gone as well.

I've never seen a burnt out cpu.
 
Try replacing the CMOS battery first, cheapest test. If that doesn't work then try other components.
Click to expand...

My experience has been that it will boot with the battery removed, as opposed to replacing it. It just won't retain the CMOS settings. I've never had a battery prevent booting.
 
Thanks everyone!

Hadn't had time to test so I hadn't replied yet, sorry for the delay. Here's what I found:

1) Very dead power supply with melted stuff on the inside (didn't notice when I first posted)
2) Dead motherboard
3) Everything else OK and currently running with different PSU & motherboard

** How I tested (in case anyone reads this later with similar problems) **

First thing I tried was a visual inspection of the motherboard for bad caps, but didn't see anything. Then, I tried a different PSU with the motherboard and found that, while the computer wouldn't power on, the southbridge fan wasn't making a screeching noise anymore. My wife suggested that perhaps the PSU was delivering the wrong voltage and causing the fan to spin at a different speed than it should be. A reasonable hypothesis?

Then I looked closer at the PSU and found that some of the components were blown/melted. I was worried then about my video card and hard drives, since they both get power directly from the PSU; I tested the hard drive in another machine and could boot from it. The video card also worked in another machine.

Knowing at this point that the old PSU was the main culprit, I tried removing the battery and resetting the cmos (thinking perhaps the motherboard was in some kind of safe mode after maybe reading bad voltages) but it still wouldn't boot. I did not, however, remember to remove the 24pin & 4 pin power connectors like akhilles suggested; I haven't read about that being required, and it's not stated in the manual. Can anyone else verify that it is a requirement or not?

I wound up swapping all my components out (except of course the motherboard and PSU) into my other 939 machine, one by one, and they all seem to be working, so I consider myself lucky.

After reading this post and scouring the internet, it sounds like my initial symptoms indicate either a bad PSU or bad motherboard, with about equal probability. CPU could be a problem, but generally seems to be rarer.
 
Good job. As I stated earlier (above), it's usually the PS that goes out, and takes other stuff with it. That's why you should never scrimp on the PS when system building, even if it means putting a $100 PS in a $25 case. You're lucky the HD didn't go with the MB, that's usually the first victim. BTW, screeching fans are usually just the bearings wearing out and not a function of PS voltage, especially Northbridge fans on the MB.
 
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