Spoiler alert. If you don’t want to know what happened, don’t read the title of this post. Too late.
I got home tonight to find that the new keyboard cable for the BBC Micro had arrived. I plugged it in and just a long beep. Doh!
I then did a lot of looking and checking and found that the left most pin on the motherboard had been bent over at some point. I bent it over and tried again. This time, beep, beep and a banner and prompt.