Diggro ALPHA 3 (Alfawise U30 and LK4 Pro clone) / does not start at all

Good evening to all,

I have just picked up a Diggro Alpha 3, and learned that it is a clone of the LK4 Pro and the Alfawise U30 and it refuses to work.

Indeed, after pressing the power button, the fans turn on, the green LED on the power supply lights up but the screen remains hopelessly off.

Input/output voltage OK
I connect to my PC => the screen lights up.
I run Pronterface => error:volume.init failed
I run a command => nothing happens
Display on the printer screen => error 4 homing failed (oooohhhh really ?????)

You need to restart your printer..... blablabla

The problem appeared suddenly after 500 hours of operation while the printer was heating up the platen and nozzle.

The question is: is there a solution, or is it the motherboard that died ?

Thanks in advance !

J.