I just received a transponder back from service. This piece had been throwing an intermittent txpndr error message on the Skyview display for the the last year or so. Recently the error was becoming more frequent and then ATC finally reported losing my signal on the last flight. I requested an RMA from Dynon as I have in the past for other items to start the formal investigation. They in turn said it needed to be return it to the manufacturer for detailed eval. Even though out of warranty, the repairs were completed without charge. I just completed a local flight and performed an FAA ADSB performance flight review which was flawless. Thank you again Dynon and staff.