R2000iA-165. R3J. Twice now this robot has started faulting with collision detection, but no collisions occurred. J5 starts SRVO-050 (collision) and 053 (disturbance). Gets worse over a couple of days and finally won't run at all. I have noticed that the four D-cell batteries will be down to 1.3 or 1.4 volts. After I change the batteries - 1.6 volts, and remaster, J5 is smooth again. It will run fine for a couple of weeks and then same thing over again. It is lightly loaded with torques averaging 10 - 20%. Anyone have any ideas?