[SOLVED] PC only power up after shorting the ATX pins...

[araujo.tiago]

Hello.

I am experiencing a weird problem with my PC. Here is my setup:

• Gigabyte B450M Gaming
• Ryzen 3 1300X
• Radeon RX580
• 24GB (16+8) DDR4 2400MHz RAM
• Corsair CX450

I am inclined to believe that I have a faulty PSU, but I need to hear other opinions to be more certain about it...

I have an outlet extender with a line filter where I plug the PC's power cord. Usually, every time I shut down my PC, I also shut down the extender. But, after a while I noticed that if I forget to turn off the extender, the next day my PC won't turn on (in other words, if I keep it energized but off). When it happens, I do some "maneuvers" (e.g. switch off the PSU and then on again) and it powers on. Buuut, it does not turns off after (the coolers keep running, despite the shut down command). Reading some articles, I found that it could be related to a dead CMOS battery... bought a new one and the problem was gone for a good time, until...

...I forgot to turn down the extender again! 🙁

Now my PC won't turns on even if I turn down the extender in the night before. After trying some stuff, I managed to discover a way to make it work: I need to remove the ATX pins from the MOBO, to force the PSU to power on by quickly shorting the corresponding pins (PS_ON + COM), and then connect the molex connectors back on the MOBO. After that, the PC turns on and works fine (I can play games for hours normally). The problem is that after this, it does not turns off and I need to switch the PSU key off with the fans running, and to turn it on again, I need to repeat the process...

Have any of you seen anything like this before? Could it really be my PSU? Or could it be my MOBO? My CPU?

Any help would be greatly appreciated.

My best regards.

 

[scout_03]

i would try another psu for test how old is this one .

 

[araujo.tiago]

It's 2 years old.

Unfortunately I do not have a spare PSU, neither a friend nearby to borrow one.

But I am aware that it might be a required verification to narrow down the possibilities.

 

[araujo.tiago]

Just passing by to say that I tested my setup with a spare PSU, and the problem persisted.

Then I left my computer in a technical assistance. It passed a week there under tests, and the technicians said me that the problem is with my GPU, for sure (they said my PC did not fail once with other GPU's). I accepted the idea, once my GPU presented some weird behavious before.

Then I picked up my PC, bought a new GPU (now a GTX 1660), replaced the old one and...

... SAME PROBLEM!

My PC only power up if I short the pins in ATX big connector first.

Considering that I tested the PSU and GPU, the problem is now between my MOBO and my CPU!

The weird part is: once my PC is powered up, it does everything without a single fail!

 

[araujo.tiago]

End of story.

Faulty motherboard.