[SOLVED] PSU Spins for split second, PC won't boot

[simon.d.morrison]

Hi,

Scoured the forums and couldn't find an answer.

I've got an old 900W PSU for my old rig and the fan died on it. PC would still turn on but I didn't leave it long as I didn't want it to overheat and take something important with it.

I've bought 2 new PSUs and having the same issue with both where when I press the power button my LEDs and fans turn on for a split second and then all turn off.

First PSU was 450w which I returned, second is 700w (cool master b700 ver2) which I still have. Specs are below so I don't think it's a power capacity problem.

I've tried jump starting both PSUs with a bit of wire

My old 900w PSU still boots up my PC so no mobo issues. Have I just been really unlucky with PSUs?

Any ideas?

PC specs (don't laugh)

ASRock A790GXH 128M
AMD 9850 phenom
2x2gb ballistic sport
1x 128gb ssd and 2 other HDDs
Gigabyte GTX 750

 

[Darkbreeze]

Almost certainly you have a faulty motherboard and the PSU is not getting an adequate (Or ANY) power good signal from the motherboard or the PSU is detecting a short or other problem with hardware and it's protections are shutting the unit off.

Either that, or something is not connected correctly. Bench testing might help find the problem, but honestly given the age of the motherboard I'd say you either have an issue with bent pins on the CPU or a faulty motherboard. Very HIGHLY unlikely that three PSUs would all do the same thing. In fact, practically impossible.

How to properly bench test your motherboard​

 

[simon.d.morrison]

Hi, thanks for the quick reply. My old PSU still works though. I put my rig back together with the old 900w one and it boots up fine.

Problem with the 900w is the fan has stopped working, hence needing a new PSU

 

[Darkbreeze]

Were both the other PSUs new?

Are you 100% sure that you've connected all the required cabling with the other two? Are any of these modular power supplies and if so, are you trying to use the cables from the old PSU with those from the new PSU? Because if you are, don't, you can't do that.

Otherwise, if it works with the old PSU aside from the fan not working, then I guess there MUST be problems with both those other power supplies even though that is unlikely. As you may know, when you've eliminated every possibility, whatever remains must be the problem however unlikely it may seem.

 

[simon.d.morrison]

Hi, yes both the 2 non-working ones were new.

They were semi modular but I've checked all the cabling and I've only used the cables that came with the respective PSUs.

I've got another PSU on order so I'll update when I get that.

Thanks

 

[simon.d.morrison]

Just a final update. I got the new PSU very quickly. Antec 650w, plugged it all in and worked first time.

I guess I was just unlucky the the first 2 PSUs??

 

[Darkbreeze]

Combination. Unlucky and probably low quality as well. Glad it's working now though. Good luck to you Simon.