If your A500 has the original floppy drive inside you won't have a problem reading past track 82. I think it was mainly the later A1200s which were burdoned with crappy disk drives.
I'm sorry for asking the obvious a lot, but have you given your disk drive heads a clean? I have inherited around 10 A500s as well as other Amigas over the years and every single one of them had problems reading disks before I put a floppy drive cleaning kit through them, which fixed them all. You can get these on eBay or from a local computer supplies or stationary shop if you're lucky. They look like a floppy disk with a white pad inside them, and you put some drops of cleaning fluid in them before running it through the drive for half a minute or so. With the Amiga, just keep rebooting after it tries reading the disk, and do it about 20 times so it has a good scrub.
