All drives failed, 40 sec restart not working - Is the EX4 toast?

Looking to help out a family member with his poorly EX4.
It displays on the LCD that all drives failed and attempts to access the GUI return “Power was lost from the system. Performing file system consistency check. Please wait.”. I’ve waited over 30 hours and given up. At times the LCD displays no drives installed and the GUi displays the message “Install hard drives and click continue”. I re-insert the drives and click continue and after a period of the GUI saying “Updating” It simply returns to the insert drives message. 4 second restart just keeps me in this loop, 40 second restart does not appear to work at all and SSH refuses connection.

So I have now bought 4 new identical WD Red hard drives. I installed them and only bay 2 came up good. I did a reset and only drive one came up good. I then did a factory reset and 3 and 4 both comes up good briefly before all drives suddenly report bad. These are brand new disks. They have all shown as good briefly but never together.
Anyone have any idea what is going on?