Question PC turn on, then turn off, then turn on again repeteadly.

[sso9]

Hello, i need help identifying the problem.
I have PC that will turn on for about 3 secs and then turn off, then about 3 secs later turn on again before turn off again. The cycle will continue until i cut off the electricity.
There is no beep at all, no display, no BIOS, all the CPU and other fans are on, there is only one light from Mobo, which indicated that it have power (it's on).
Before this the PC is fine, never turned off abruptly or crash (at least i can not remember the last time it crashed).
I have tried clean the PC, made sure all the cables plugged correctly, clear and change to new CMOS battery, place 1 RAM in every slot.
Specs:
- Asus p8Z77-M (LGA 1155)
- Intel i5-3570
- Corsair Vengeance 2 x 4 GB DDR3
- Radeon 5670
- PSU Dazumba 600W

I have one other PC, tried it and can still run, so i test the VGA and HDD in there and it's fine. Sadly it is an even older PC (20 years with lots of uses and still running quite fine although sometimes it crashes) with LGA 775 and DDR2 RAM, so i can't test the RAM or CPU in there.

I removed all other cables except the 24 pin, 8 pin, all the fans and front panel. I remove all RAM and the problem is still the same. Based on my searching if PC turned on without RAM it will either not power on at all and make beeping sound or it will turn on fine, but no display. With that, can i remove the RAM as the possible problem? If yes, then the problem is either Mobo, CPU, or PSU then.
Is it possible to know the exact problem? I'm short of money, so i can't really buy something just to test. The other thing i can test is changing PSU from the older PC, but i'd like that to be the last option. I'm scared if the newer PC still does not work after changing PSU, somehow the old PC will not work after the PSU put there again.
Can someone help tell me what step i can do to know the exact problem? Any help will be very appreciated. Thank you.

 

[Lutfij]

Welcome to the forums, newcomer!

PSU Dazumba 600W
That does not look like a unit worthy to be called a PSU. I would source(borrow, not buy) a reliably built 550W unit from a friend or neighbor and see if the issue persists.

Is it possible to know the exact problem?
Troubleshooting is a process of elimination, working your way through a checklist. If you went out and bought a part because you assumed it was the culprit, you're almost at the point where you'll be building a new PC with hardware meant for troubleshooting. This is why we suggest borrowing part from a friend or neighbor.

Moved thread from Components section to Systems section.

 

[sso9]

Welcome to the forums, newcomer!

PSU Dazumba 600W
That does not look like a unit worthy to be called a PSU. I would source(borrow, not buy) a reliably built 550W unit from a friend or neighbor and see if the issue persists.

Is it possible to know the exact problem?
Troubleshooting is a process of elimination, working your way through a checklist. If you went out and bought a part because you assumed it was the culprit, you're almost at the point where you'll be building a new PC with hardware meant for troubleshooting. This is why we suggest borrowing part from a friend or neighbor.

Moved thread from Components section to Systems section.

Thank you!

Based on my case, can i eliminate the RAM as the possible problem?
Can i do something else first before changing PSU, to know whether the Motherboard or CPU is the problem or not? Sorry but i don't think i can borrow PSU from someone else.