And usually the schematic too. Few suppliers will provide them. Some will as part of an expensive service manual. I had to troubleshoot a problem with my MFJ remote autotuner (way out of warranty) and having the schematic was a huge help. Word to the wise: These days customer service has mostly gone online, as a real time "chat" with a service agent, or via email or webform which starts the process for somebody to get back with you. You can try using the phone but mostly that will result in frustration, if you can even find a way to phone them. Many companies have made it quite difficult to find their customer service phone number.