Please help me to check

I have a samsung medison sonoace r7 not working. When turned on, the screen does not light up and after 15-20 seconds it turns off and then turns on again. this cycle is repeated several times. I can't understand the reason. Plugged in a third party keyboard. When you press the CapsLook key, the light on the keyboard does not light up. Checked the RAM 100% okay. The processor seems to be fine too. I decided at the beginning to buy a cheap computer Congatec (conga-ca) which is not quite suitable for this device. Installed, CapsLook began to light up and the device stopped turning off. True, this computer did not have the necessary video ports for sonoace r7, so it was not possible to turn on the monitor (as I thought at that time). After that, I decided to buy exactly the computer that is indispensable for this Congatec Conga-BM45 device. And now here's the surprise. When I installed the required new computer, the problem recurred. When you press the CapsLook key, the light on the keyboard does not light up and after 15-20 seconds the device turns off. I'm confused and can't figure out why this is happening. Is the new computer not fixed too. I think maybe the problem is hidden in the adapter to which the device's monitor is connected. Please help me to check...