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Computer Will Not Turn On?? Switched out Power Supply, Getting Green Light on Motherboard

i built this PC about 1 and half ago. here are the specs

Asus P5WDH Deluxe Motherboard
intel dual core processor
ATI x1650 PCI express video
6 GB of ddr2 6400 RAM
3 500GB Sata drives
and a SATA DVD burner
vista 64bit

i have replaced the power supply on this computer 2 times before. yesterday the 3rd power supply went out. all i had was a new 400w to replace it with. i didnt think it was enough so i just hooked up the primary hard drive to get it back running.

well i replaced it this time and i get no response from the computer. all i get is the green light on the motherboard when i turn the power on.

here is what i have tried:
i have tried to hook the power button up every way i could. i have completely dissassembled the computer and put it back together. i have even tried removing everything from motherboard including processor hooked up power and power button and it still will do nothing but give me that green light.

i will say when i hooked up the new power supply i might or might not have smelled something burning. i couldnt tell if it was just the new power supply or a mild electrical burning.

also i have this computer behind a APC 1500 backup/surge.
i have even tried plugging directly to a different socket that i know is working and still nothing.

any ideas? is it another bad power supply, not enough power, or motherboard?????
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bignadad
Asked:
bignadad
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2 Solutions
 
adolphus850Commented:
Your APC is probably what is blowing the power supplies if you have had to change it that many times.

Unplug the computer from the mains and press the power button.
Reattached the power to the mains and turn the machine on.  does it turn on?  If not, remove everything installed apart from the CPU, CPU heatsink and fan and turn it on.  Does it beep?

Adol
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CallandorCommented:
When a power supply goes, it may knock out everything connected to it - that is why I advocate getting a high quality power supply.  Yes, it is possible your motherboard or video card or RAM were affected by the power supply failing.  You will have to swap them out to determine which one(s) it is.
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bignadadAuthor Commented:
i use ultra power supplies. is that a decent quality?

Unplug the computer from the mains and press the power button.
Reattached the power to the mains and turn the machine on.  does it turn on?  If not, remove everything installed apart from the CPU, CPU heatsink and fan and turn it on.  Does it beep?
no, and no. cpu fan never starts. all i get is that green light on mobo.
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adolphus850Commented:
so if i understood that correctly, the green light does not turn on until you press the power button?  Sounds like a faulty motherboard i'm afraid.  Try unplugging everything from the power supply from the motherboard and turning it on then reconnecting it again and turning it on.  Obviously unplug the power first.

Adol
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bignadadAuthor Commented:
no. the green light on mobo comes on when i turn on power supply. nothing happens when i press the power button. could be be a defective power button?
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CallandorCommented:
You can bypass the power button by directly shorting momentarily the two pins on the motherboard where the wire from the power button connects.

>i use ultra power supplies. is that a decent quality?

Never heard of them.  I recommend PC Power & Cooling, Seasonic, and Akasa.  The good ones will have an 80+% efficiency and provide over 36 amps of current on the +12v rail.
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bignadadAuthor Commented:
okay it is a ultra x connect ps that i am trying to use now
max output 12v-20a
i tried hooking this ps to an old computer and the computer turned on without a problem
i hooked it back to my computer and nothing. i took the power button out of the other computer and tried to hook it up and still nothing. that green light comes on when i connect power but thats it. i have the main power connected and also a 4 pin connector. is that right?
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CallandorCommented:
Yes, that's right - the 20 or 24-pin connector and the square 4-pin connector should be plugged in.  If nothing starts, you're probably looking at a damaged motherboard, since you know the power supply works.
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bignadadAuthor Commented:
is 400 watts enough for what i am running?
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CallandorCommented:
Which cpu do you have?  I would use a higher rated supply, around 500-600 watts, only because I don't know that brand and I tend to err on the cautious side, knowing the dangers of a supply that is too small.  In actual practice, I have measured my setup running an E6600 cpu, 4GB RAM, 7 hard drives, a tuner card and an optical drive and it was less than 200 watts, but I was using a Seasonic 550.  You can unplug everything except the motherboard, one RAM module and the video card, just to see if it will POST with a smaller ppower supply.
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