My Uni I’s motor for the ink drum has trouble starting. In the past occasionally when I turned it on, it would not turn and would softly hum, but turning it off and on again would restart it. Now it mostly won’t start turning, though if I manually push on the drum it will start. I think the oil levels are ok, but I am not 100% sure of that. If I need to add more oil, it looks like our motor’s fill plug is horizontal, is that not unusual?