Proliant ML350 G5 front LEDs blinking red

[Osama_]

Hello,
This is a detailed description of the problem:

-Hardware:
- Proliant ML350 G5
- One processor mounted on processor 1 socket
- Two SAS hard disks
- 2 x 1GB RAM
- PCI ethernet card

-Just before the problem:
The system was working OK. I was running Linux Mint from a live USB stick. I shut down but the system stuck at the shutdown screen. So I long-pressed the power button. The server came down and never got up again.
-The problem:
When I connect the power cable, only the power LED lights in green. When I press the power button, the two aforementioned LEDs blink in red and I hear the low sound of the power supply fans but no other fan runs.
I noticed in the front panel two blinking red led. Long-pressing the power button turns off the system (power supply fans) but the two LEDs keep blinking.

- My diagnosis:
By referring to the user manual, I found that the two blinking LEDs are the internal health LED and the External health LED (power supply). For the internal health LED it is mentioned:

Red = System critical. To identify the component in a critical state, refer to system board LEDs

and for the external health LED:

Red = Critical power supply failure

So, I noticed my motherboard LEDs and referred to System board LEDs section. All LEDs  in the motherboard are off except for:
- PPM2: blinking in amber.

System LED and color: PPM failure (amber) 
Internal health LED color: Red
Status: 
- PPM has failed.
- PPM is not installed, but the corresponding processor is installed.

So, this LED blinks because I don't have a processor power module for the second processor as I have only one processor (at socket 1)
- AC power: Green. The user manual says that:

Green = Power supply is on and functioning

- Two LEDs blinking just below the RAM sockets (they were blinking the same way when the system was functioning well). I found nothing about them in the manual.

-Actions I took:
I followed the suggested solution here:

https://community.hpe.com/t5/ProLiant-Servers-ML-DL-SL/ML350-G5-won-t-boot-red-internal-health-LED-undocumented-system/m-p/4831025#M112555

get system off power,

get battery out of systemboard, pull all the memory and put 1 back,

look on the inside of the lid, on the drawing there is a system maintenance switch, switch number 6 on,put battery back,power back on and see what happens after a couple of minutes on the screen

Of course, the screen displayed nothing.
I suspect that the power supply is damaged, but I have doubts because:
- This happened suddenly while the system was running well.
- The power supply LED in the motherboard is green.
Any explanation?
Thanks