Analogue and digital electronics and circuits.
Shy Roomba!
My Roomba 560 seemed shy as it was backed into a corner with a dead battery every time I came home. So, as I had done many times before, I cleaned all the LED sensors under the bumper and fitted a new battery. No change. I eventually found this site about the nine beep dance of death. Ah, more dust in the sensors, I thought. Testing showed the faulty right bumper switch. Taking it apart I was pleasantly surprised by the use of optical rather than mechanical switches. Still, dust could still be a problem.
Replacing a neon indicator with a LED
Neon indicators on electrical items do not seem to last for a very long time. They just blacken. A LED would be a good replacement, but they do not work directly with mains AC voltage. Here are some options to consider.