One easy way to distinguish between a transmitter problem and a computer problem is to find a friend with the same transmitter style and an AI computer, and switch transmitter IDs with him/her. Pressurize and power up both pairs.....if your transmitter works with the other computer, and the other transmitter does not work with your computer, it's your computer that is the problem. Etc.It just might be the transmitter. Because my gear was done at my home in Mexico, I couldn't get the battery replaced this time when I had the computer done. I was planning on taking it back after this visit to get that done. The error message I got at the end of the first dive was "Prev Dive Error." The reason I'm thinking it's an error with the computer is that it hasn't cleared.