Quote Originally Posted by mackrackit View Post
Just thinking that when the board moves close to the big motor a strain is put to the connector / solder joint / etc.

Sounds like you checked all that as I thought you would have.

Do I have this correct? The only problem is -- when board gets to close to the big motor, RA.4 does not receive a signal. Every thing else is working "OK".
Yes, exactly. When the board gets to close to the big motor, RA.4 does not receive signals coming from the Allegro hall-effect chips.
Anything else is working fine and as expected (serial communication, big motor's position other motors tracking etc. etc.).