The other interesting thing is, that under any firmware ( version and vendor)
Clock and date are always same 01 AM 1st of January 1970.
I could not find clock settings beside TIME ZONE.
Are there any and how to access them.

About time, that's more software related, as it should take it from the Satellite (or you can update it with the ntpd like things over internet).

One thing you could try, is when your box doesn't work. Turn off for like few hours and see if it boots when you turn it on again (after few hours) and if it does the same symptoms as previously, or does it just doesn't boot (like if the firmware was corrupted at all if you try to boot few hours after).

Admin

Yup, it is doing exactly as you described.
After few hours it does not properly boot. ( not showing any video on hdmi, and network is not active). Its actually just like firmware corruption.
Interesting, I just tested yesterday if its on, its stays on whit out any issues for hours....
So, according to my experience, it can be two things...
- weak/blown capacitator...(I checked them all visually, not one is damaged or swollen).
- bad/broken ROM(flash) chip.
Third...far possibility is generally weak/unstable external PSU.
This possibility I plan to eliminate latter today with brand new PSU.
If this doesn't help....than its one of the upper mentioned issues.
thank for the patience...

Exactly, so we are near to finding the exact cause, and most probably fixing it,

Well done,

Admin