[jgeorge]

Alan, Thanks for good suggestions. I will try to wrangle a scope from somewhere into the school to check encoder signals. And do the output bit test trick as well. Should give a good picture of situation.

Kevin, Thanks for reply. I will build the board. But, why does it work sometimes? Just marginal you think? I was going to stop all prints and see if it works better as the TX buffer intr. taking too long might interfere with the encoder phase B read causing the problem. Maybe in some versions of code, the print time is synched with the encoder phase B just right! In any case, I agree with you that it appears I will have to build board.