Computer will randomly not turn on

By ryans123 ·
I was just wondering if someone knows what might be going on with my computer. I just built my new computer and i booted it up loaded windows and everything was running fine. I restarted a few times for windows updates without a problem. Then for some reason when i rebooted again my computer would not power on. No posts or anything the hard drive light would go on for half a second and then nothing. So i unplugged my computer waited 15 min and then plugged it back in and everything worked. The same thing happened the next day.

The temperature is good and is running at around 45 C. And everything looks like it is connected properly.

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Possibly bad power supply.....

by ThumbsUp2 In reply to Computer will randomly no ...

The power supply may not be strong enough to power everything up and is getting an overload situation. Unplugging it for a time will reset it.

To test this, try holding the power butten in for 5 seconds while you're turning the machine on. This will allow the hard drive to spin up to speed (or at least closer to speed) and get the juice it needs before the system actually boots. If this works, replace the power supply with one that has more power.

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by ryans123 In reply to Possibly bad power supply ...

I will try this next time it happens.

I have a 650W power supply right now.

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I'm more interested in what the 650W is trying to power ...

by OldER Mycroft In reply to 650W

Can you post with the full spec of all the hardware that draws power. Things like:

Motherboard, RAM, Graphics card + RAM, Hard Drive(s), Optical Drive(s), USB ports, USB equipment, Keyboard, Mouse, Joystick, type of speakers, Headphones, Microphone, size and number of case/mobo fans.

Anything that can be simultaneously sucking the power.

Make and model of PSU too. It may be peak-rated @ 650W but incapable of sustained delivery ?


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by ThumbsUp2 In reply to 650W

... Remember, just because you purchased a 650W power supply doesn't mean that it's putting out 650W. Test, test, then test some more.

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I have to agree with ThumbsUp 2 here I would be looking at the Power Supply

by OH Smeg In reply to 650W

And just because it has a sticker on the side saying 650 W doesn't mean that it's actually producing that amount of power on all Rails.

I've seen 550 W Antec PS which are by no means cheap units not work from New out of the box like this. The fact that unplugging will allow the system to start tends to point to a Power Supply Issue and remember just because things run like CPU & Case Fans doesn't mean that everything is getting the amount of power required in Current or the correct Voltage.

You need to actually measure the Actual Voltage & Ampage coming out of the Power Supply. If the system acts like this or will power on 1 in 20 times the Power Supply is not working properly.

I've seen some owner builders replace the Video Card, M'Board, CPU, RAM and then bring it to me to be repaired because it's not working. When a Known Good PS is inserted not only does it work properly but when tested all the replaced components work Perfectly. These PS pass the Elchepo PS Testers which keep the PS running and make a LED Glow when plugged into the ATX Power Connector to the M'Board.

Basically if you think that the PS is working you need to change it with a Known Good to confirm that it's working when you have problems like this. Also while we are at it if you get a message on the Monitor that there is no Connection to a Video Card change the PS after you have confirmed that the Monitor Lead is actually plugged in. That message is a certain Sign of a failed power supply that will run the Case Fans and so on but not the computer.


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Suspect heat-induced MB grounding

by nepenthe0 In reply to Computer will randomly no ...

Peconet Tietokoneet fielded a query similar to yours within the past couple of months. He recommended a thicker insulating washer and nylon screws/nuts. Apparently the processor heat caused enough warpage to cause a grounding short.

I'll look for his post, and edit this with the exact URL if I find it.

See TR posting of 19 Mar'08:

Rick/Portland, OR

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