Mac SE Error 0000000E 000000FF

From what I could find, It seems to be a bad CMOS battery. I couldn't find much more. Good luck though.

Few points to add:

Was the logic board recapped and cleaned?

Did you try and change or reseat the memory?

When was the last time the machine worked properly? Last week? Or 10 years ago?

CMOS battery (actually it is called the PRAM battery on these Macs) would not cause much problems on these machines if it goes flat, however it might leak after all that time and destroy the logic board…