# Solved: Power supply light blinking/clicking, computer won't turn on



## unicorncove

We got a Compaq Presario S6500NX from a friend who had upgraded to another computer and we can't get it to work. It ran fine before he brought it to us, however, once we got it here and tried to power it up it wouldn't start at all.

On the power supply in the back the green light blinks and clicks rapidly when the cord is plugged in, and pressing the power button does nothing at all.

Interestingly, a few minutes ago I took it out of storage, (we got the computer months ago and gave up when we couldn't get it running) plugged it in by itself and it powered up just fine, the fan turned on and everything! So I opened it up and cleaned out some of the dust (I didn't have it plugged into a monitor or anything, I just wanted to see if it was still doing the same thing it had months ago) and, lo and behold, when I tried to turn it on again with everything plugged in, I got the blinking/clicking green light and no power up. 

What could be the problem here? I know the whole thing isn't totally shot because it DID power up just fine a few minutes ago. But now we're back to the blinking clicking light (instead of the steady green glow that usually happens when the power supply cord is plugged in). It leads me to believe that something's loose, but I don't dare mess with the power supply box unless I know what I'm doing...

Another question is, if the power supply isn't fixable, would it be possible to replace it with the power supply from my working Compaq Presario 6000?


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## unicorncove

Addendum:

When I followed the instructions here I found that the light would go off entirely when I unplugged the power supply connector from the motherboard. Does this mean that the motherboard is defective? The power supply? Why did it turn on before and not any more?


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## Megabite

First thing to try is to re seat everything and check and re connect all the connections
If you are not comfortable about this have someone do it who is.
If it is the power supply you can't fix it you will have to replace it.

Something could have come loose on the board or connections I would try that first as usually when a power supply fails it does not come back on again like yours did.


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## unicorncove

Yup. Did that. Reseated everything. Nada. Unplugged stuff and tried to see which item had an effect on the blinking light. The only thing that did (the light didn't come on at all when I unplugged it) was the power supply connector to the motherboard.

What I don't get though, is why it came on at first and then wouldn't come on after? I've read of other compaq owners having similar problems. I suspect it has to do with the fact that it was sitting untouched for a number of months. What else can I do?

And as far as replacing the power supply, can I replace it with the power supply from my compaq presario 6000? Do you think that would work?


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## Megabite

You could try the power supply you mentioned if the connections are the same.
If the same thing happens it could be the CPU has come loose or the Thermal paste has dried out.

Check here for info on re-seating the CPU and applying thermal paste

http://www.arcticsilver.com/arctic_silver_instructions.htm


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## unicorncove

Would that cause it to be able to turn on though? Because it did turn on fully when I first plugged it in from storage. And now it doesn't.


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## Megabite

Process of elimination I'm afraid.


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## unicorncove

No, I mean that if the CPU has come loose or the thermal paste has dried out, would it allow the computer to power up sometimes and not others? Because when we got the computer, it didn't work. Today, months later, I was actually able to turn it on. Then after shutting it down I wasn't able to turn it on again. 

I will give it a try as soon as I am able to get ahold of some Arctic Silver. In the meantime, is there anything else I can try?


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## Megabite

Try pushing down on the Heatsink ontop of the CPU


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## unicorncove

Nothing. Is it worth trying to switch out the the power supply with the one from my working compaq? Or is that likely to mess up my working computer?


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## Megabite

Should be alright if the connections are similar


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## unicorncove

All fixed. I replaced it with the power supply from my older model and it works fine now. Thanks.


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