Brother International HL 1240 Service Manual - Page 146

CHAPTER 6 TROUBLESHOOTING I-16 Black spots User Check (1) If the problem is not solved after printing a few pages, the drum unit may have glue from label stock on the photosensitive drum surface. Refer to Step 1 in the table below and NOTE in the previous page. (2) The drum unit may be damaged. Install a new drum unit. Possible cause Drum unit Step Check 1 Are the spots at 94mm intervals? (The problem is not solved after printing a few pages.) Fixing unit High-voltage power supply PCB failure 2 Are the spots at 79mm intervals? (The problem is not solved after printing a few pages.) 3 Is the problem solved after replacing the high-voltage power supply PCB? Result Remedy Yes 1) If toner or glue remains stuck, wipe it off gently with a cotton swab. (Refer to NOTE in the previous page.) 2) If the photosensitive drum is scratched or deteriorated (exposed), replace the drum unit. Yes 1) Check and clean the heat roller with a cloth dampened with alcohol. 2) Replace the fixing unit. Yes Replace the high-voltage power supply PCB. I-17 Black band Possible cause Step Check Result Remedy Corona failure Corona failure 1 Is the wire cleaner at its home position? 2 Is the corona wire dirty? No Return the wire cleaner to its home position. Yes 1) Clean the corona wire. 2) If the problem still appears after cleaning, replace the drum unit. Ground contacts ➁ ➁ 6-36