First thing I would try would be to take the system246 from the not working side to the working side (make pictures before starting just in case later you dont remember what cable goes where).
Then you'll know if the system246 still works and if that's the case, then you can check the other elements like PSU.
My 2 cents.
Then you'll know if the system246 still works and if that's the case, then you can check the other elements like PSU.
My 2 cents.