why does the cpu boot loop

[Thunderbolt 3]

cpu working fine ytd. this morning power on i hear the fans spinning then the fans + all internals off..... 1-2 secs later it power on its own, the fans spin for 1-2 secs then off for 1-2 secs. it nv reach the *beep* stage. keep looping until i off the power at psu switch behind.
waited 1 min switched on the psu switch and boot up this time no prob all boot up as normal.

any idea why cpu like tt?

 

[jtjt00]

List down all parts of your rig like those on the right -->

 

[hawthorne]

Sound like PSU problem

 

[LiLAsN]

You better check the PSU cable that is connecting to the top left of your mobo. It is the one personally powering the CPU. I ever made a mistake of not connecting it when I was reassembling my build on a new case and the same symptoms occur.
If it happens again and re-adjusting the cable on both ends doesn't help, you can try replacing the cable with another one that your PSU should have and if possible, connect to a different slot. But if your PSU under warranty, might as well replace the whole PSU and its cables altogether.

 

[undead102]

Exact same symptoms happen to my old asrock board as well. Had to reseat the ram to fix the problem temporarily. Turns out the mobo is the main culprit. Mobo dead eventually. Replace it problem solve.

 

[jtjt00]

Without TS rig info, we can only make wild guess and TS will look cute if he/she follow advice here.

 

[VoltechSG]

cpu working fine ytd. this morning power on i hear the fans spinning then the fans + all internals off..... 1-2 secs later it power on its own, the fans spin for 1-2 secs then off for 1-2 secs. it nv reach the *beep* stage. keep looping until i off the power at psu switch behind.
waited 1 min switched on the psu switch and boot up this time no prob all boot up as normal.

any idea why cpu like tt?

It sounds like a PSU problem. By any chance, are you using Seasonic X series PSU?