Okay... so they mention here to apply cleaner to the 'switches,' and depress them over and over, what are those? Sorry I'm not down with the terminology.
As you look into the floppy drive slot from the front of the A3000, at the left front of the drive are two black prongs sticking up. When a disk is inserted one prong is pushed down, closing a switch that indicates a disk is in the drive. The second prong will stick up through the write protect hole if the disk is write protected or it will be pressed down if the disk is writable, closing the write protect switch. If you have a high density drive then there will be another prong and switch at the right front.
It may be possible to clean the switch contacts without cleaner, just by depressing the prongs over and over. In either case, it's probably best to remove the A3000 cover to get at the switches.