Ricoh G188 Service Manual page 334

Service Call Conditions
No. Type
CTL
636 SD Card Error
D
Expanded authentication module error
There is no expanded authentication module in the machine.
The SD card or the file of the expanded authentication module is
broken.
There is no DESS module in the machine.
01 -
1.
2.
3.
No. Type
BICU control data transfer abnormal
A sampling of the control data sent from the BICU reveals an
abnormality.
CTL
641
D
1.
2.
G188/G189
Details (Symptom, Possible Cause, Troubleshooting Procedures)
No expanded authentication module
Defective SD card
No DESS module
Install the expanded authentication module.
Install the SD card.
Install the DESS module.
Details (Symptom, Possible Cause, Troubleshooting Procedures)
Defective controller board
External noise
Defective BCU
Replace the controller board.
Replace the BCU.
3-38 SM Appendix