• Code: 391.928
• Description: Drum CRUM M Not In Position. The Imaging Unit (M) CRUM is not in the proper position (loose CRUM).
• Remedy: 1. Remove and reinstall the Imaging Unit (M). 2. Polish the connection terminals between the Imaging Unit (M) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (M) CRUM with dry cloth. (When cleaning, do not use Imaging Unit cleaner, etc.) 3. Check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (M) P/J113 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (M) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (M) CRUM for damage and foreign substances • The Imaging Unit (M) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (M) • Imaging Unit CRUM Coupler Assembly (M) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.929
• Description: Drum CRUM C Not In Position. The Imaging Unit (C) CRUM is not in the proper position (loose CRUM).
• Remedy: 1. Remove and reinstall the Imaging Unit (C). 2. Polish the connection terminals between the Imaging Unit (C) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (C) CRUM with dry cloth. (When cleaning, do not use Imaging Unit cleaner, etc.) 3. Check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (C) P/J14 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (C) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (C) CRUM for damage and foreign substances • The Imaging Unit (C) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (C) • Imaging Unit CRUM Coupler Assembly (C) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.940
• Description: Drum CRUM Y Data Broken. The system detected that the data written to the Drum (Y) CRUM and the data read from the Imaging Unit (Y) CRUM do not match.
• Remedy: Remove and reinstall the Imaging Unit (Y) and check for improper installation. If no problems are found, replace the Imaging Unit (Y).

• Code: 391.941
• Description: Drum CRUM C Data Broken. The system detected that the data written to the Imaging Unit (M) CRUM and the data read from the Imaging Unit (M) CRUM do not match.
• Remedy: Remove and reinstall the Imaging Unit (M) and check for improper installation. If no problems are found, replace the Drum (M).

• Code: 391.942
• Description: Drum CRUM C Data Broken. The system detected that the data written to the Imaging Unit (C) CRUM and the data read from the Imaging Unit (C) CRUM do not match.
• Remedy: Remove and reinstall the Imaging Unit (C) and check for improper installation. If no problems are found, replace the Imaging Unit (C).

• Code: 391.943
• Description: Drum CRUM Y Data Mismatch. Incorrect authentication area data was detected in the Imaging Unit (Y) CRUM.
• Remedy: Remove and reinstall the Imaging Unit (Y) and check for improper installation. If no problems are found, replace it with the correct Imaging Unit (Y).

• Code: 391.944
• Description: Drum CRUM M Data Mismatch. Incorrect authentication area data was detected in the Imaging Unit (M) CRUM.
• Remedy: Remove and reinstall the Imaging Unit (M) and check for improper installation. If no problems are found, replace it with the correct Imaging Unit (M).

• Code: 391.945
• Description: Drum CRUM C Data Mismatch. Incorrect authentication area data was detected in the Imaging Unit (C) CRUM.
• Remedy: Remove and reinstall the Imaging Unit (C) and check for improper installation. If no problems are found, replace it with the correct Imaging Unit (C).