oh the IIfx rom gives you the chime of death as well?

i don't know how the IIfx rom would work in your Iici.

get a magnification glass and inspect the traces,

do you have the ability to remove your rom's?

like use a heat gun, if they are soldered… maybe that battery acid leaked under the roms.

maybe you could pull them out and you will see some eaten traces.

he has the same issue with this amiga 500, had to pull the IC, to do some repairs.

http://www.youtube.com/watch?v=Aj0Qbrs_3Gk