[SOLVED] PC keeps turning on and off indefinitely unless I power cycle the PSU before turning on the PC

[RendyIrawan]

Hey guys, I'm having problems with my desktop PC and I hope someone here could help me. I have an old PC running a Pentium Dual Core E2160 (1.8Ghz) on a Gigabyte GA-P41T-D3P motherboard and I'm using an Enlight 420W PSU. I'm not sure all of this is relevant to the problem that I'm having, but I'm just stating it here as an FYI.

So anyway, to further elaborate the problem I'm having, Here's how I usually would use the PC:

1. Connect the power cord to the PSU
2. Switch on the PSU
3. Press the power button on the case
4. Use the PC like normal
5. After I'm done, I would shut it down and the PC shuts down and turns off like normal as well.

It's when I want to use the computer again afterwards that becomes a problem. If I just press the power button to to turn on the computer, the computer would do this:

1. It would power up for about 2 seconds
2. Turns off by itself for 1 second
3. Turns on again for another 2 seconds
4. Turns off again

Here's a video of this strange power cycle loop:

View: https://youtu.be/2WYdkq6as7I

This would go on infinitely and I would have to switch off the PSU to stop it. After I switch off the PSU and wait for about 2 seconds the computer would turn on (CPU, PSU, and case fans spinning) for just about a quarter of a second, then I would switch the PSU back on. Only after that I could press the power button on the case and the system would power up like normal and I would be able to use the computer. But if I had to use the computer again after shutting down, I would have to do the power-cycle-the-PSU thing before I can switch on the computer. If I power cycled too quick (before the quarter-second flicker) and tried pressing the case power button to turn on the PC, that strange infinite power cycle would happen again and I would have to power cycle the PSU and wait properly. Any ideas why it's behaving like that?

So just to clarify: other than this issue, the PC works just fine. This problem bothers me just a little bit because everytime I want to use the PC, I'd have to reach to the back of the case to power cycle the PSU.

I tried using another PSU and disconnect all peripherals (keyboard, mouse, all USB peripherals, all HDD, SSD, and CD drives), but the problem still occurs, it seems like a motherboard issue. I heard that power issues usually is caused by a bad capacitor, is this one of those cases? Any suggestions would be highly appreciated. Thanks!

 

[Darkbreeze]

The first thing you need to do is blow out the CPU cooler heatsink. I can clearly see that it is packed full of dust. The power supply probably ALSO is, so blow that out along with the rest of the system as well. Be thorough. Do NOT use a vacuum. Use an air compressor or cans of compressed air available at most office supply or grocery/Walmart type stores.

Then, if that fails to help the problem, it is very likely, given the symptoms AND the age of the motherboard, which by the way is pretty ancient by modern standards, it's highly likely that you have a faulty motherboard. Make certain that all fans, especially those on the CPU cooler and power supply, are functioning normally because if they are not they will likely cause the exact symptoms you are seeing as well.