During the Covid lockdown I was bored (and far from my family) but, by chance, near old computers of mine. So I watched Youtube videos and decided to open/test them all.
Atari 600 XL: still working
Texas Instruments Ti-99/4a: starting but garbled output, know issue, apparently a relatively easy fix
Amiga 500: dunno, lost the power supply (and have to be super careful not to mistake it with the power supply of the C128: same form factor, different pin-out, guaranteed to fry the computer).
Commodore 128 (not 128D, sadly): still working and about 1/3rd to one half of the 5"1/4 floppies still working too.
Macintosh Classic (which I think is the successor to your SE): still working but I took care of first removing the battery on the motherboard, which had started leaking.
Amiga 2000 and 1200: no battery right? (unless you've got an expansion card)
Even if you start it, at least just open the SE and remove the battery today (I take it the SE has battery). Just open a YouTube video showing how to do that.
So: take the battery/ies out, check the power supply, try to turn them on.
Now the other issue is capacitors that begin to leak after 30 to 35+ years: I haven't tried yet to "recap" these machines but... "one day".
All least I took the battery out of the SE!