Unplug the 520 unit and plug a standard video cable into the composite out RCA jack on the rear of the A500. Plug the other end of the video cable into the video-in on your TV. Turn on the Amiga 500. You should see a b/w screen. If not, try changing the Denise chip. There is a good chance that the Video Hybrid IC, near the Denise chip is bad. If something is plugged into or unplugged from the RGB port while the Amiga 500 is on then the Video Hybrid IC will be damaged and must be replaced. They are very hard to find. I sell new Commodore Video Hybrid ICs for only $24.95 each or used ones for $15.00 each. :-)
