I bought the Simcheck A300 a few days ago and was happy with it, the only downside: the cdu. So I searched if there isn't a new cdu for it, and with that I saw the fmc expansion, I bought it directly and installed. First there wasn't any fmc, but I managed to install it properly afterwards. But I didn't had time to fly as it was late at night and I needed to sleep, that was yesterday. Today I finally had time to fly the A300 with fmc but directly after I wanted to configure the fmc, I sadly needed to realise, that whenever I want to insert the letters into the fmc they don't appear. Whatever I did, nothing showed up. Please help me fix this.