Power problem: PC turns quickly on & off for no reason.

[chrestomanci]

Hello, I have a problem with my PC (Specs as "My System" in my profile).

Basicaly it cycles between on and off every ten seconds or so, regardless of if the power switch is pressed. If I turn the switch on an the plug on the wall, the PSU starts and I hear fans going, then after a few seconds it goes off again, a few seconds later and it comes on again, in a continous cycle. I don't see any POST messages, but the system is not realy on long enough to see any.

Pressing the power or reset buttons on the case make no difference. The only way to stop it is the unplug the whole system.

The obvous first step is to borrow a a spare power supply, and I should be able to get one from work, but has anyone else seen anything similar? I did wonder if perhaps the fault was with the motherboard not correctly signaling to the power supply that it needed to turn on and stay on.

Yesterday I had similar but less severe syptoms, where if I pressed the power button on the case the system would boot normly and stay on, but I still got cycling when the system was supposed to be off. When the system was running I went into the PC heath screen in the BIOS, and checked that the voltages from the PSU where correct. They where OK.

Any other ideas? Thanks.

[chrestomanci]

The obvious first step is to borrow a a spare power supply, and I should be able to get one from work, but has anyone else seen anything similar? ...

I borrowed a spare PSU from work, fitted it and the problem has gone away, so it looks like I will be buying a new PSU tomorrow.

Because I have a small case, I have had trouble in the past with overly big power supplies, or power supplies that have long cables, where the cables get in the way. Can anyone recommend a compact power supply preferably with short cables?

A few years ago, I saw the Silverstone ST50EF-PLUS-SC that has shorter than usual cables for small cases, but I can't find it stocked anywhere.

I am aware of that Silverstone do a set of shorter cables for their modular PSUs, but adding together the cost of a replacement cable set, and a modular PSU (which is overpowered for what I want), come to rather more than I want to spend.

[kwai]

try looking for a modular PSU instead if you dont want cables clogging up your case, generally psu's are ever so slightly smaller if they are of lower wattage, but dont quote me on that!
I have a ocz fata1ty 750w which is modular, and its lovely!