Roller door now rolling down as well as up

Today I got a servicedude out from Steel-line doors to service our garage roller door and remote operation stuff. He managed to tell me that the unit I had the primary door connected to had a faulty logic board, so he swapped the two units around.He didn’t remember to swap the radio receiver with it though. This meant that my remote control didn’t actually work with the powered-on door opener/closer unit. Damn! When Chip came over for coffee this arvo, we spent 5 minutes looking at both units, and very quickly realised that the radio receiver needed to move in order to enable the opening and closing remote control functions. One very quick swap later, and joy had returned, along with a working carkey-sized transmitter unit which actually did tell the open/close unit what to do. J will be pleased