Some cartridges are not quipped with the resetting mechanism for the drum unit. If your unit is not responding at installation this probably is the case. If so, please follow the reset procedure given below.
Enter the diagnostics menu by turning the machine on and and within 4 seconds press: "CLEAR," "EXPOSURE MODE," "CLEAR," "EXPOSURE MODE" (Exposure mode is the button on the far left). All of the display will go blank. Using the 10 and 1 keys (copy quantity), enter "24", press "PRINT," enter "7", press "PRINT", again. The machine is now reset.
If the above instructions do not reset your machine, try turning the machine off and restarting it.