There really aren't any repair shops anymore. There is one you can find online: Home Page
Finding parts for some radios is really tough with something as old as that one. Your best bet would be to upgrade to something new, with digital capability and since Black Friday is coming quickly, it might be wise to visit the Radio Shack near you and pick up something new. Scanner Master is another one to check out, too. Scanner Master - Police Scanners by Uniden Bearcat, AOR and Radio Shack.