Dell E515dw User Manual page 312

4. Push down the lock lever and take the toner cartridge out of the drum unit.
5. Unpack the new drum unit.
6. Put the toner cartridge firmly into the new drum unit until you hear it lock into place.
NOTE: Make sure you put the toner cartridge in correctly or it may separate from the drum unit .
7. Clean the corona wire inside the drum unit by gently sliding the tab from left to right and right to left several times.
312 Routine Maintenance