While no resonse 17 is more common, these two seeme to happen to each of us at least once. I took my handset apart and reset the ribbon to the display which cured that error. Unless it becomes chronic I'd just note it and move on.
Having a spare handset on hand seems to have cured other complaints from my original handset so having a replacement in the wings may scare your handset into behaving too.
Power or connectivity issues are the most common reasons for those No Response errors but corrupted firmware is not unheard of. There has also been some discussion about intermittent connections causing firmware corruption but as far as I know nothing has been proven conclusively.
There are two motor controllers on the one MC board, one handles the Azimuth motion, the other takes care of Altitude. The No Response 16 is one of the motor controllers (probably the azimuth ... lol) and NR17 the other (altitude).
An actual failure of the MC board is just about always hard (not intermittent) so you are probably fine there.
My experience has been that the 12 volt input prong on the control panel base is a bit wonky. Look closely and you will see that the central prong is actually split. You want to GENTLY pry that prong apart slightly so that it will make a more secure contact with the power cord. ALSO... make sure you have the right power cord. The correct power cord has an inner diameter that is just a hair less than other power cords that look just the same otherwise. I had had a problem similar to what you describe and once I made these corrections I have not had a recurrence of "no response 16". Good luck. check out the following site as well for more information http://nexstarsite.com/OddsNEnds/PowerConnector.htm