Had both the Comm and Xponder repaired at Free Flight Systems located in Waco, Tx. They do good job, a little pricey, but they are up front about the costs, and stand behind their work.
How recent was this repair work done? Waco is much closer to me than Gulf Coast at Lackland, FL who has done the repair on my units. They did very good work for me but they are farther away and quite expensive. When it comes to avionics I want what I have to work perfectly and cost is a distant second but if they are still working Terra hardware and you were pleased with the results, I'll try them next time.