As always, Stein's words are golden. A few months ago, I had the local avionics guy certify the biannual transponder check on both my RV's at the same time. The old encoder coupled with the transponder in the -6A took almost 6 minutes to fire up, while the internal encoder in the Dynon fired up instantly. The technician said this is quite normal saying he has seen some older encoders take up to 15 minutes to function properly.Yep, the old encoders (that being separate boxes not the internal ones provided in all the new EFISes which are instant) need some time to "warm up"....it's normal!
Cheers,
Stein