The hard drive doesn't spin at all with the trapdoor ram enabled? Completely silent? Doesn't show in Early Startup screen? Could be some bizarre address conflict?
A1200 probably uses a 2.5" hard drive. SupraDrive probably uses a 3.5" drive. Much bigger, higher power draw, yadda yadda.
A500 can power a drive through the side connector, as you've seen and as evidenced by
these mods (which I've done on mine), but if it were me, personally, I wouldn't run a high draw mechanical drive that way. Look for a CF or SD adapter, instead. Just .02 cents.
Possible to try the 500XP with a different, smaller drive? Or one with a lower power draw?
