The 4000 does not have a composite out or any out other than a RGB port. Yes the A520 will work with ALL Amigas! You will also need a special floppy drive for the Amiga. You can get some older chinon PC drives that will work with the Amiga and they are actually drop in replacements. I have two stock 4000's and they both had Chinon drives. I found some Chinon FZ-357 from a PC Salvage yard and they can be easily modded to work on the Amiga. Do a search on here for Chinon FZ-357.
Good luck with your A4000, it is a very nice machine. Just make sure to check the battery and remove it if it is furry!
