Background changeover unit failure [fi-5120Cdj #2 , 048005 , c2]

Hi Vivek,
Thank you for contacting Fixya.
When a background switching malfunction occurs, "E" and "F" will display alternately on the function number display panel of the scanner.
Background changeover unit failure error is detected in initial checking at power on. Probable causes:
- Insulation material damage of BW motor cable or the damage of the wire in the motor. - Defective lamp or CCD or CCD cables. - CCD Connector disconnected. - Defective Control PCA.
Solution:
Wipe the top and bottom glasses located inside the ADF with the Cleaner F1 (or isopropyl alcohol) and check if the problem persists.
1. Does the same symptom occur after turning OFF and ON the scanner? Press power button of the scanner for more than 2 seconds to turn it OFF, and after more than 2 seconds elapse, press the power button to turn the scanner ON. 2. Check if the cables between the Control PCA and the BW motor damaged? Are the connectors connected correctly? Check & confirm the position of the BW motor and check the cables. 3. Check Is the CCD cable F or B damaged? Or are the connectors connected correctly? 4. Check if the OPT Unit is installed correctly? 5. Check if the white reference works properly? If not, then replace the BW Motor. 6. If the above do not resolve your issue, then you may have to replace the Control PCA or Optical unit to see if the error is resolved.
Hope the above information is helpful.Please revert if you have any doubt.

Regards,

TechSatya