I've just repaired an old Amiga A500+ that had been stored in our loft for many years. On removing the cover and screening I was met with a horrible sight, the NiCad for the RTC had leaked extensive and caused corrosion to the mainboard which is a very common problem apparently. The FDD also required some attention but most of the discs didn't work due to bit-rot and other issues.
I came across details of a floppy emulator made by Gotek and this together with downloaded disc images has given the machine a new lease of life. The set up disk that was supplied with it also has a folder of Atari ST software so may be worth investigating.
Here's some info on YouTube.
https://www.youtube.com/watch?v=SOhRBR66DS0
John.