Posted by BillS on July 29, 2008 at 14:23:59:
In Reply to: Fellows FS180 Optocoupler error posted by Drew on May 14, 2008 at 17:01:38:
I'm pretty sure the optical coupler is mounted on the back of one of the DC servo motors, each of which drive the ballscrews to move each different axis.
These motors will have cables and electrical connectors. You might find that a cable or a connector is damaged. Look for high flex areas in the cable, or external damage that may have been caused in transit. Clean the connector contacts if you suspect corrosion.
I would disconnect each servo motor cable one at a time, start the machine, and maybe the one that doesn't change the diagnostic error no. is the bad guy.
These servos are electrically controlled by closed loop feedback electronics (the opto-controller is the sensor that monitors motor shaft position), and if the diagnostic test didn't run, then the motor would likely run full tilt to its extreme position and just sit there, possibly causing damage.
If you identify a bad cable, the easiest thing is to buy a replacement. It can be repaired (I've done that cuz I was cheap) but finding the small wire that's broken can require much patience. If wire fatigue is responsible for a broken wire, replacing the whole cable is probably best - other wires will break before long.