How to check what is broken in the server?

Question

Server equipment

Hello!
The HP ML 350 G6 server worked when turned on, suddenly turned off and went into reboot. And so in the cycle. At the same time, it was connected to the UPS, there were no problems with electricity. All this happened with me. The reason for the behavior has not yet been clarified. Exactly as he did not launch it. I had to pull out the plug, when I turned it on again - the fans screamed, a second and it goes into reboot. During this time, of course, nothing is displayed on the screen.
There is a suspicion that the problem is in the power controller. For I pulled out all the equipment and tried to start it with 1 processor, I tried to change the power supplies to known good ones. Tried to reset NVRAM, pull out the battery, it's useless.
On the front panel, where the LED responsible for the status of health shines red, which means critical health. Prompt if who faced - where to dig. I plan to remove the motherboard, inspect all the same power controller. The conders look normal, there are no swollen ones, there are no hot chipsets either ...

Answer 1

Based on the symptoms, the motherboard is dead.
Source: personal experience.

Answer 2

POST - the map can show you useful information about the state of the hardware.
In addition, you can find out about the state of the hardware by connecting to iLO, and there are POST codes there