I  Bought 6 sets of DT7/DR16 about 2 years ago.  Didn't have time until now, to discover that only 2 of 6 DR16 actually work.  That was done by switching with known working parts to isolate the problem.

Naza FC would not recognize DR16 (Naza flashing yellow and Naza Assistant showed no radio connection), even after DR16's "green light" was shown to be bounded to the Transmitter.

Too late to return.  So I am looking into how to fix it, since I can't buy DR16 by itself.

What is the EXP pin on the DR16.  What is it for ?  Some sort to tie down to reset or re-program?

I am having  the same problem. have you solve it