Ricoh FT 3013 error code E 21? how can it be fix

· Scanner home position sensor failure
· Defective scanner motor
· Defective main board
· Defective dc power supply board
· Incorrect scanner drive wire position
· FU202 on the dc power supply board open (blown fuse).
- Action -
Turn the main switch off and on.
Check the position of the 1st scanner sensor actuator.
Actuated De-actuated
Does the scanner motor rotate when the main switch is turned on?
No Yes
Correct the scanner drive wire position.
Check the voltage at CN106-2 on the main board.
24 volts 0 volts
Check FU202 on the dc power supply board.
Good No Good
Replace FU202
Replace the dc power supply board.
Check the voltage at CN105-1 and 6 on the main board.
24 volts 0 volts
Replace the main board.