After a couple of phone based troubleshooting sessions with George, the RA gearbox and the GTOCP3 control box were shipped back to AP. They replaced a spur gear and a cluster gear, updated the control box firmware to 4.19.2 and programmed the control box with new PEC data.
Result: Excellent tracking, pointing and accurate parking. Best of all, stars in an unguided 5 minute exposure are perfectly round with my 10" Newtonian.
