Brother MFC9100C Service Manual page 187

Messages on the LCD
SET INK HEAD
PLS OPEN COVER
CHECK SCAN LOCK
PC BUSY OR FAIL
If only an alarm beep is heard without any message on the LCD when the equipment is powered up,
the ROM or RAM will be defective.
The CPU on the main PCB has detected no print head mounted
when attempting to read the property information obtained by
the head property detector and stored in the EEPROM on the
head PCB.
To display the relating detailed error code, use maintenance-
mode function code 82. (Refer to Chapter V, Section 3.14.)
If this message appears, open and close the scanner unit. The
message may disappear if opening/closing the scanner unit
removes the error. If the error persists, the "MACHINE ERROR
X X" will appear instead of this message.
The output of the CCD HP sensor does not change because:
1) The CCD lock is placed in the lock (backward) position,
2) The CCD HP sensor is defective, or
3) The CCD motor is defective.
After connected with the host computer, the equipment has
received no response from the computer. (A communications
error has occurred.)
VI - 3
Probable Cause