As folks stated already, could be the crystal. I had issues last week with my KV-1, I thought it was the crystal too, but turns out the transmitter itself went bad. Only reason I found out before requesting for help in a thread was because both my PIII and KV-1 are on the same frequency and I didn't realize I still had the KV-1 on when I started up the PIII. You can imagine how elated I was not having to troubleshoot the problem. The crystal from the KV-1 and transmitter were verified to still be working in my PIII transmitter as well.