I have a custom computer, with ATX power supply motherboard. Today all of a sudden a problem occurs.
I pressed the power button on the front of my case. Nothing. About 20 secs later it lights up, fans start, it boots up and into Windows. I'm at my desktop and haven't done anything yet when it powers itself down.
About 20 secs later, it starts itself up again (at this point I have just been a witness - not touching anything). This time it turned itself off more quickly at about the Windows boot-up process. About 60 secs later it booted itself up again and now is in a cycle but the time between booting back up becomes longer and booting down shorter.
I have tried the following in different steps to try to narrow down a problem:
1. Removing 1 stick of RAM at a time. No difference with either stick.
2. Unplugging everything except RAM, CPU, Video Card. No difference.
3. I unplugged my video card - no difference in booting up delay but it had a long beep when it finally started up indicating no card.
4. Unplugged everything, cleaned everything, replugged in everything and made sure it was all tightened. No difference.
The more I turn it on by pressing the power button in the front of the case, the longer the delay is before it will actually turn on. It's sitting at about 4 mins now between pressing the button and the system starting. The motherboard light is on whenever the power supply is connected and on, by the way.
Is this a faulty PSU?