I wonder if some other people have experienced the same problem with the transponder.

When I start the plane it takes a while before the transponder starts blinking. I was told that it was because it was cold and I had to wait some time before it starts transmiting.

It ususally takes up to 10 minutes for it to start blinking. Any ideas?

Do I need to change that transponder?

btw the transponder is a AT 150