Power shutdown seconds after starting up

[jonnyr]

I started a thread in new build computers but as I seem to be narrowing the problem down to the PSU I'll set out the salient features here as well.

Newbuild comprises

Asus M3a32-MVP Deluxe motherboard
Samsung SpinPoint F1 500GB SATA-II 16MB Cache
OCZ 2GB (2x1GB) PC2-6400 gold Series DDR2 (just trying with one module)
AMD Phenom X4 Quad Core 9750 2.40GHz
Scythe Mini Ninja CPU Cooler
Corsair HX 520W ATX2.2 Modular SLI Compliant PSU
Asus DRW-2014L1T 20x DVD±RW SATA Dual Layer Lightscribe ReWriter
Coolermaster Centurion 534 case
Asus ATI Radeon EAH3650

Everything connected together I switched on and the fans and HDDs powered up then the power failed. Following advice elsewhere I dismantled and started building up one component by one on the table top.

I plugged in one stick of ram, the CPU, cooler and video card which I connected to a monitor. I plugged in the 8 pin and the main power connector and powered up by shorting the power pins. .... voila! it started up and allowed me to get into the bios. I attached a floppy drive, powered up succesfully again and updated the bios with no problems. Everything seemed rather stable.

I then tried attaching the HDD. Powered up and ... shutdown. Exactly as when everything was in the case. I removed the SATA cable and just powered up with the HDD plugged in to the PSU. Again ... shutdown. I tried another HDD which I was planning to use for creating a RAID array, a Samsung spinpoint HD320KJ. Again powered up and again ... shutdown.

So at this juncture all fingers seem to be pointing at the PSU unless anyone has any other opinions. Is it possible that the 520w supply is simply not enough to power the board, CPU, graphics card and memory such that when one HDD is attached everything shuts down or is it likely to be faulty? Alternatively does the problem remain elsewhere still to be discovered.

Any help would be gratefully appreciated.

 

[chookman]

unplug the GPU and power up with the hard drive powered. If it shuts down it maybe the hard drives. If it doesnt its the PSU

 

[jonnyr]

Aargh!!

Done as suggested. (Had to rely on a fan plugged in to see if the system was up or down!) No HDD plugged in - no problem. HDD plugged in - shutdown. If it was one drive I could understand and accept it was the drive but I'm getting the same result with three different drives. But if PSU can power the GPU and the DVD would the HDD need so much more power such as to cause the problem. Or is it possible that the HDDs need some sort of initial burst which the other components don't need which the PSU can't cope with.

 

[chookman]

hmmm... 5v rail on the PSU could be dead or shorting

 

[jonnyr]

Ditto hmmmmm!

I plugged the HDD into another PSU (unfortunately old 20 pin connector so can't use on my new mobo). Powered up and disk started spinning with no probs.

Tried something I probably shouldn't have but with interesting result. Went back to my new rig. Started up with no HDD plugged in to psu. No problem as usual. Leaving the power supply on (ie fas still spinning) I then attached HDD to power. Started spinning and stayed running! Tried it with my other HDDs with same result. If I power up with HDD already attached I always end up with an immediate shutdown.

Before I decide that it is the PSU for sure, is there any way a faulty CPU could cause this kind of behaviour. It's the only component I haven't changed!

 

[jonnyr]

It was the PSU. Bought a new one. All connected. All systems go. Vista installed a breeze. Am up and running. Thanks for all feedback.

 

[chookman]

Good to hear it, bit of a strange one though