Pc wont turn on but has power

[russ8585]

Hi,

My PC went off unexpectedly and now wont turn back on. When I try to turn it on the case lights up for half a second but that’s it. There seems to be power as the fans will start to turn, then stop. There is also a power light on a usb splitter which is plugged in the back.

I was thinking it was a power problem but if the case lights up and the fans spin then it must have power.

Anything else it could be?
What could I try?

I have uploaded a clip here if it helps:

[MEDIA=youtube]yhFgklEeo4o[/MEDIA]

[veeg]

Hello

Probably a faulty psu.. Or a bad power switch.

@Evan Omo

[Bruce]

my money is on the PSU, but have also seen stuttering stop/start symptoms like the fans are showing with faulty motherboard as well.
but first, why not strip that thing back to bare metal and get rid of all that dust!

[russ8585]

Hello

Probably a faulty psu.. Or a bad power switch.

@Evan Omo

Hi, Whats the differnce between the psu and power switch?

[phillpower2]

PSU = power supply unit and the power switch is the power on button on the case.

Please provide information about your computer, this includes is it a custom build or brand name such as Dell or HP, if it is provide the model name or series number (not serial) if a custom build post the brand and model name or number for the MB, add on video card if one is used, the RAM including the amount and the PSU (power supply unit) providing these details will enable us to better assist you.

[Evan_Omo]

Hi russ8585, Welcome to PCHF!

I agree that its probably a faulty power supply or a bad motherboard. I would look at swapping out the power supply first and if that doesn’t allow the computer to power on, then its most likely a faulty motherboard. Especially since the machine powered off out of the blue, the power supply may have failed.

What power supply does your computer have?

[Rustys]

To add what @Bruce stated you should also replace the thermal goop between the CPU and Heat sink.

[russ8585]

Thanks guys. Its a custom built machine I believe (deff not a brand anyway). I’m not too sure whats in it as Ive had it a good 5-6 years. I’m planning to buy a new one but not for another year or so.

I’ll start by cleaning out all the dust first and then look at the PSU .

Is the PSU hard to replace? Im not too tech savvy with PC components.

[Bruce]

if you had to pick a part to replace, the PSU would be one of the easiest. (right behind a CD unit )

it simply unscrews from the back, you unplug all its cables, and then screw in and re-cable the new one.
it you are ‘not too tech savvy’ then take plenty of pictures on how the old one is connected first.

expect to pay something like $AUD120 for a unit in the 650-750watt range.
I couldn’t see the old PSU wattage on the sticker (top left corner inside the case just in case you were wondering ) and you seem to have an add-on graphics card - so when buying a new PSU, go higher rather than lower. but really, probably a 500-600watt one will do considering the PC is around 5 years old, so something like $AUD80 may do.

as a quick and dirty fix (no dust pun intended), remove the memory sticks and that graphics card, give those and their slots and brush down, reseat them and see if that works. you may get real lucky and it was just dust shorting things out.

[russ8585]

Thanks. Ive tired cleaning it out but no luck. ive got the PSU out so I will try replacing it. Fingers crossed.

[veeg]

Do you have can air to use to blow out the dust?

[Bruce]

from the age and amount of dust, albeit unlikely, you couldn’t rule out just bad and/or oxidise contacts as well.
so if you have just ‘blown out’ the dust, that may not be enough, which is why I would physically remove those components for cleaning.

[russ8585]

Hi All. I replaced the PSU but the problem remains. No change. What could I try next? Ive already cleaned the dust out.

[veeg]

Ok then i suggest you power down the pc and opened it up and with a bright light ,start checking for bulged capacitors and or popped or leaking.. Most of the time you will know when you see it and most of the time the evidence is on top of the cap.. A normal capacitor will look like a smooth cylinder ..

[russ8585]

Ive removed all the harddrives etc. Cant see anything wrong with the capacitors. Ive changed the cmos battery too. Still nothing.