Computer powers on for a second or two, then turns off

[bradkenyon]

I bought parts from newegg a year ago, to put together a inexpensive tower.

Since then, something was wrong, it would randomly shut off.

That went on for a year, up till recently, it shut off, and now when I try to power it back on, it has power for a second or two, then shuts off. No beeps, nothing on the monitor, not even long enough to press the cd rom button to open the cd rom drive.

It seems that the power supply is working, because it powers up, for a second, but maybe it is the motherboard that makes it shut off instantly? Or maybe the CPU is bad, because when it would shut down randomly, the CPU usage % was at 99-100, and it was only that high when I was downloading from BIT Comet Torrent downloads.

What do you think I should trouble shoot first?

Thanks,
Brad

 

[baronvongogo]

troubleshoot the easy things first RAM, mobo pin connections take the USB ones out. Then graphics card if u have a spare to try out. Unplug all nonessential parts too and work from there. I would also look at testing out the PSU which is most likly the cause possibly the mobo too.

Also was the computer sluggish a lot? freezing etc?

 

[bradkenyon]

Well, when the computer ran, it ran pretty quick. I have a feeling that from the computer randomly shutting down a lot, it was enough to kill it, it being the mobo or the CPU.

How would I test the RAM, taking it out, and booting it up w/o the RAM in there?

Thanks for the speedy response!

 

[baronvongogo]

depends how many sticks u have if u have 2 then you can chop and change using 1 stick in each dimm slot then the other etc. Id unplug all hard drives ,cd/dvd drives etc have the basics plugged in.

 

[bradkenyon]

thanks for the tips - i'll try that tonight!

if the thing beeps with no RAM in, that is a good sign, because the thing doesn't even power on long enough to hear beeps.

 

[baronvongogo]

well let us know how you get on lets hope its not the mobo or CPU

 

[RicoDirenzo]

No one even mentioned the posibility of it being the Power Supply. I would do a pS swap with one you konw is good and see what happens. Could be a very cheap fix if it is the PSU>

 

[baronvongogo]

troubleshoot the easy things first RAM, mobo pin connections take the USB ones out. Then graphics card if u have a spare to try out. Unplug all nonessential parts too and work from there. I would also look at testing out the PSU which is most likly the cause possibly the mobo too.

its just easier to test the little things before getting a PSU for most people

 

[b0dge]

If you dont mind a bit of messing about, try turning power off completely, then unplugging all the internal PSU plugs (from mobo, hdds, Graphics cards etc), then plug the power cord into the back of the PSU and find the green wire on the 20/24 pin mobo plug (pin 14)(16 on a 24 pin Connector), use a paperclip or short piece of wire to short between the green cable and a black one (any black one will do). The PSU should power up for as long as you hold that link there. If it doesn't, it's shot.

If you're worried about doing it, then I suggest you don't. If not, just be careful to only short the green to black, and nothing else!

 

[bradkenyon]

So I made a bunch of unplugs and power ups.

Conclusing, it will stay powered on without being plugged in the dvd drives, hard drive, and the ram in.

If the hard drive is plugged in, it will stay on for 5 seconds, but if everything is plugged in - it'd be on for a second or two.

If the ram is plugged in, and nothing else, it stays on forever, or until i turn it off to trouble shoot another thing.

If I leave one the dvd rom's plugged in, it will stay on for 20-30 seconds, then both dvd's plugged in, it will turn off after 3-4 seconds.

If the hard drive is plugged in w/ the ram, it automatically turns off, same w/ just the hard drive plugged in, and nothing else plugged in.

I have a feeling that the power supply doesn't have enough juice.

PSU:
Mustang Model: LC-B350ATX (MAX 350W)

I am pretty sure it is. If it is, that will be a cheap fix.

Let me know what you think, and what kind of power supply should I get (on newegg) - max watt? 450? Current one is 350