I have seen in some of my manuals that the position and velocity encoders have an external regulated 5 volt power supply that feeds the encoders. do you have these or is your 5 volt power supply coming only from the DSP card? you indicated you have changed the opto isolators on the DSP card, do these have anything to do with the 5 volt power supply being sent to the encoders? I would change the whole DSP card, if you dont have regulated 5 volt power cards to encoders.
