A little more detail about the hardware. This is a Toaster 4000 Amiga
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Unfortunately I sold my 1080s monitor and an A520 would be the cheapest solution to see what's going on. I found a couple on ebay and put them on my watch list but it's going to take me some time to get one.
There's a small chance that your Miggy is getting to the insert floppy screen, but...
I don't think it is getting to the insert floppy screen because nothing happens when I put a floppy in,
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...as nothing happens on inserting a floppy disk I highly doubt that.
From my A4000 with CSPPC I know this sort of problem.
In intervals of 1 - 1.5 years it simply refuses to boot (or it boots and freezes shortly after).
Reason here is that the contacts between motherboard and CPU board tend to corrode over time.
Up to now I always could solve this problem by cleaning the contacts between motherboard and CPU board with commercially available contact sprays.
Have you already tried this?
When I got it, it had some battery leakage and the MB and first simm slot had some corrosion from it and I got a green screen. I removed the battery and cleaned the simm socket and MB and it worked from then on.
I threw out my battery as well when I noticed it started leaking (luckily before the mobo was contaminated). I didn't replace it and automatically retrieve the actual date/time from the web as soon as I go online instead.
It doesn't look like there's been any further corrosion from any residue from the battery. The area around the battery on the MB looks clean. I took out all the simms and cleaned them and the sockets with contact cleaner. Possible that the chip ram simm has gone bad but not too likely. I've got a box of unsorted 72 pin simms and I might have one I can swap to test this.
You should try to clean the connectors between CPU board and mobo as well this way...
