I don't think it's a good idea to run the toaster with the case open, for rf and grounding reasons. The toaster has a grounding copper strip thingy next to the floppy which should contact the metal A2000 case cover.
Did you put some kind of non-conducting spacer between the Toaster board and the p/s? Most setups I've seen use a rubber grommet or something so the two cannot touch. I don't think this was your problem but a tip for the future. Interestingly, though the A2320 ff has a plastic shield on it's backside, the Microway ff has none (good idea to add something to eliminate accidental shorting.
