All fans start running when PC gets plugged in...

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SuaveLemon

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System Specs:
Processor Brand: AMD Athlon(TM) 64 X2
Processor Speed: 2.4GHz
System Bus: 2000MHz
Cache Memory: 1MB + 1MB on die Level 2
System Memory (RAM): 2GB
Hard Drive Type: Serial ATA (7200 rpm)
Hard Drive Size: 400GB
Graphics: NVIDIA GeForce 6100 and nForce 430 MCP
Modem: 56 Kbps
Network Card: Built-in 10/100 Mbps Ethernet LAN (RJ-45 connector)
Dual Booting Ubuntu 8.04 & Windows Vista (*shudder)

Ok so about a year ago I had installed a new 450W ATX power supply (Can't remember the brand atm) so my system could handle a new video card, everything went smoothly. Now one of the fans in the power supply had it's bearing wear out and started making all kinds of scary noises. So I pulled the power supply out of the machine, dismantled it and replaced the fan. I re-installed it and went to turn the computer on and got nothing. So I checked everything and strangely enough the power cord didn't seem to be working, so I replaced that. As soon as I plugged in the power supply, all the fans in the pc started running at max speed.

This surprised me because as far as I know the power supply wont start powering the system, and none of the fans will start until it gets feedback that the power button has been pushed.

Now all that happens is the fans run at max speed and the HD light on the front of the case lights up (But the hard drive doesn't spin up). The power button does nothing (even if I hold it down).

Luckily I kept the original power supply from before I upgraded (had only been used for a total of 1 week) so I removed the 450W version and the video card and replaced the original power supply. I plugged my monitor into the on-board vga port and plugged in the system. SAME THING!! So i'm sure that the problem does not lie with the power supply. I'm beginning to think that I killed something on the motherboard. I was using an anti static band, but I wonder if maybe i've cracked a solder joint or something. Just to be sure I checked the leads on the power supply with my multi-meter and everything seemed to check out.

What I really want to know is if there is anything other than a bad motherboard that could be causing this issue? Or any other troubleshooting steps I might have missed? I'd really hate to buy a new MB just to find that the problem is still going on.

Thanks in advance for the help!
 
Not sure of your experience level - but i would NEVER suggest to somone to take apart a power supply. It just isn't safe and could easily kill you.

Try resetting the CMOS battery on the motherboard.
Test the power leads coming from the power supply to ensure that they are providing the correct volts with a multimeter. If not, try a few different connectors to see if all are bad, or just the few you are using.
 
I'm quite experienced with working with capacitors and high voltages, so i wasnt all that worried about the power supply. And like i said, I did check the leads of the power supply with the volt meter and all the connectors are providing the proper voltages. I never thought about the battery, I'll give that a try when i get home from work. Thanks for the insight, it's always nice to get a second opinion.
 
Hehe no worries. Sorry didn't see you had already tested those, and as long as you are experienced.

Try resetting the BIOS with the CMOS battery and see if that fixes it. If not I would agree with your assessment that the MB has been damaged somehow (rare since you were probably grounded).
 
What brand/model was that 450W PSU?

It may seem unlikely, but because you said the fans started running at max speed, it could be that the PSU surged your PC. This can happen when you use cheap PSU's.
 
I cant remember the exact make at the moment, but it was relatively cheap. But i did have the same problem when i used the 300W power supply that came with the PC. I think i might replace it too (just in case). I'll let you know if removing the battery makes a difference.
 
You should buy a quality PSU, such as one from Corsair, Silverstone, PC Power & Cooling, Antec... etc.

Something around 500-600W will do fine. You may pay a little more than you wanted, but you have the assurance that it will last a long time and never cause problems.
 
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