I was given an Oce 5120 plotter, and dropped into a shop to get a new cartridge. Pulled the carriage over a bit to the right to get the cartridge out.
When I ran the plotter up at home, kept getting a 'Carriage Error - Turn Off/On' Message. I have Googled the problem and others have had the problem. No-one can tell me the solution.
I guessed that the carriage had gotten out of sync, and kept positioning the carriage at a new position near the LHS of the plotter. Same problem.
Guessed that the cartridge should be over the rubber seal that presses against the print head. Had a careful look, position it, AND all fixed.
Posting this so others can fix their problems. DO NOT manually move the carriage.