As the title of the topic states, a working MK111 decided to spontaneously stop working. I successfully built two MK111 modules. One continues to work flawlessly. The other also worked - I was able to adjust both potentiometers to make the LED on the board blink. Suddenly, the LED just stays on continuously. No amount of adjustment to either pot makes the LED blink. I checked all the solder joints and re-seated all the components and everything looks fine. Any suggestions? Could it be that the 555 IC failed? Is it possible that the relay suddenly failed? I don’t hear any clicking.