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Please help! problem with turning on pc!

Last response: in Components
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April 13, 2010 10:04:53 PM

HI there, so my question basically.. I am having a lot of trouble trying to get my pc to actually turn on. Its not the standard, "pc won't turn on question" because, if i do get it to turn on... it runs fine and never shuts down by it self or anything like that.

When i actually got it on, i didn't want to leave the pc running for so long, days at a time, so eventually i shut it down, and the next day have problems getting it going again.

When i hit the power button, the lights flash for about 0.5 sec, and all the fans spin for a bit. In the past after a few tries to get it on it would work, now i could stand there for hours probably, flipping the switch and trying to get it on again.

Now i don't know much about hardware, but i have tried removing and reinserting the things i could, like power supply, ram, graphics card...dont know how to remove CPU tho...

and helps or tips on getting my computer to start would be a big help! thanks

More about : problem turning

April 13, 2010 10:12:00 PM

Do you have a different power supply you could possibly try in it? It might be a power supply issue, though if it stays on once its on, thats a weird issue. Try to borrow another PSU if you don't have one- it is worth a try.
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April 13, 2010 11:30:59 PM

I agree this is almost certainly a faulty power supply and should be the first thing that you change. If it is not a faulty power supply then the problem becomes more interesting, report back here if it is not.
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April 14, 2010 1:17:28 AM

If this is an older pc it could also be bad capacitors on the motherboard. This is the same symptom I had on two different boards and the capacitors were to blame.
on the right had side of http://www.badcaps.net/ there are photos of boards with bad capacitors. Caps, as they are nicknamed, are the tin can things and they should be flat on the top and there should be no brown junk on or around there bottom.
in the first pic you'll see manyof the tall caps along the bottom of the board are domed on top - they should be flat.
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April 14, 2010 3:55:08 PM

Popatim- good call. Haven't seen a board that would have trouble booting, but then when it did successfully boot, stay stable that way. Caps, either in the PSU or the Mobo make the most sense as a possible cause.
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April 16, 2010 8:57:16 PM

Hello. thank you for the replies.

Firstly, all the capacitors on my ABIT AN8 mother board are fine, no bloating at the tops and no oozing of electrolytes out the side.

Secondly, for the power supply, i removed a power supply from an older pc and was going to attach it but i noticed the old power supply did not have a connector to the mother board that has 4 pins in a square. On the motherboard, the spot for that connection is called ATX 12V1. When this is unplugged, the fans do not even slightly move but there is still a light on the mother board.

Is there a way in which i can plug a different connector to the mother board to get the same affect? or will i have to search for a different power supply that has this 4 pin square connector?

thanks
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April 16, 2010 8:59:52 PM

You will probably need a different power supply to test with then as you DO need that 4 pin connector- its the CPU power:-)
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April 17, 2010 1:02:04 AM

You don’t necessarily need the four pin connector, but on some motherboards you do and on some you only need it if you are using a power hungry graphics card. Try it and see it won’t do any harm.
If the computer powers on even if it doesn’t boot up then you have proved that the power supply is the cause of your problem.
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April 17, 2010 4:22:15 PM

Hello! another update...

so just now i plugged in my old power supply (without the 4 pin connector). The lights and the fans on my pc all turn on right away - except for the big fan on top of the CPU. Now these lights and fans stay on for about 5-6 seconds before they all turn off at the same time, the computer monitor doesn't power on at all.

Then i did the paper clip test on the "newer" power supply and the fan on the back of it start to spin for about 3-4 seconds then turns off.

And strangely, doing that test on the older power supply wont turn on its fan at all, no matter which black and green connectors i put the paper clip in.

So does this conclude the power supply is definitely at fault? or could there be something else? thanks
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April 17, 2010 7:22:55 PM

Like I said- that 4 pin connector is the CPU power. That means it will power on the Mobo and other parts, but won't detect the CPU and thus won't boot, and won't be able to turn on the the display or anything.
Most likely though, this does mean that the PSU is the issue as it will at least get everything on for a few seconds, as opposed to fractions of a second.
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April 18, 2010 12:47:51 AM

Not all motherboards require that the four pin connector is fitted for the computer to work. You have proved that the power supply is the cause of your problem as now it starts up with the new power supply albeit for a few seconds.I think that the newer power supply is bad as it should not power down if the paper clip is fitted.
Replace the power supply with the correct type and I am sure that your computer will be ok.
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