Emil wrote:
A longshot but maybe worth a try - have you checked whether your rc is set to two-way or one-way communication? During the last years of it's active life (screen only shows a few pixels nowadays) my Beolink 5000 could change from two-way to one-way without no particular reason. If you have had no batteries in for a while that could maybe trigger such a reaction.
It is otherway around.
Standard the BL5000 is 2-way, which can be set manually to one way. If a powerfaillure occurs, then the BL5000 falls automatically back to 2 way.
The BM7000/system 7000 handles 2 and 1 way without any problem.
Could indeed be one of the buttons which is stuck. Try the camera trick (optional: while inserting the batteries)