Error code "0000FFFF" "00000002" points to a Ram issue.
There are several versions of the Mac SE logic boards around. The logic board's standard setup is for 1MB of ram = 4x 256KB modules.
If you want to use another setup, you either have to change a jumper near the ram modules or remove 1 or 2x resistors near the reset/interrupt switch.
It's best if you post a large photo of the PCB so we can see if the current setup is correct or assist you which resistors need to be removed.
There are several versions of the Mac SE logic boards around. The logic board's standard setup is for 1MB of ram = 4x 256KB modules.
If you want to use another setup, you either have to change a jumper near the ram modules or remove 1 or 2x resistors near the reset/interrupt switch.
It's best if you post a large photo of the PCB so we can see if the current setup is correct or assist you which resistors need to be removed.