Brother HL-L2312D Online User's Manual page 209

9. Turn the drum unit as shown in the illustration. Make sure that the drum unit gear is on the left side.
10. Use the numbered markers next to the drum roller to find the mark on the drum. For example, a dot in column
2 on the check sheet means that there is a mark in drum region "2".
11. Turn the edge of the drum unit towards you while looking at the drum surface to find the mark.
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