Hello, it seems simple but I consult before, I set out to change the focus of a 10-year-old patrick, it has no frost or anything weird, quite common. They sold me a led bulb that does work, but when I put it on it doesn't turn on. Any advice?? Everything is together with the part of the focus with the wheel where you select the temperature, so before you reach me ... could it be something else?

Having no "no frost" has no electronic board. A common focus is going well ... thanks people.