Elitedesk 800 G3 won't boot up (boot loop almost 20s up -> 3s down)

[suniron]

Hello,

My PC Elitedesk 800 G3 mini 65W does not start.

More precisely, when I press the power button, the fans spin and the power LED lights up (white) for about twenty seconds and then everything goes out.
There's no reaction or detection on the USB ports or on the external screen (HDMI or Display port).
Also, a white LED remains lit on the motherboard with the indication **"CR1 AUX "**.

I have the same symptoms if I don't connect anything other than the power supply.

Everything was working fine until I wanted to change my SSD and I changed some options in the BIOS, in particular the power supply for the USB front ports and the SATA (see the topic I wrote at the time because I had a problem with the USB power supply https://h30434.www3.hp.com/t5/Desktop-Boot-and-Lockup/USB-ports-has-stopped-working-during-boot-proc...).

I use the 90W power supply. If I connect a weaker power supply, it's detected and I get a series of beeps + LEDs confirming the detection of a bad power supply. In my opinion, there's no problem here.

I've also tested the manipulations indicated in the HP user manual, such as holding down the Power button without power, or pressing the button to reset the CMOS, or removing the BIOS battery for a few seconds.

I've run out of ideas and I'm quite frustrated because the system was working fine before I changed the port power option in the BIOS.