I currently have a paper jam message that comes up right after self test. I replaced the sensor board n9a-3144-00, and it did not help. I have checked the entire unit for any jammed paper and found none. I have also installed the drum heater assy per my customer. occasionally a ROM error will pop up upon startup, but it disappears almost immediately. The ROM error is very intermittant. Any suggestions would be very much ap-preciated