Ricoh FT5535 Service Manual page 191

Yes
Does the drum rotate properly?
Yes No
Check drum drive mechanisms such as the drum drive belt and the drum
pulleys.
Check the following points:
CN115-3 (Charge PWM)
•
(1) If the signal stays LOW after the Start key is pressed, replace the main
control board.
(2) If no drum charge voltage is applied to the drum charge roller even if the
signal changes to a 5V pulse signal, replace the CB high voltage supply
board.
CN105-2 (Transfer PWM)
•
(1) If the signal stays LOW after the Start key is pressed, replace the main
control board.
(2) If no transfer voltage is applied to the transfer belt unit even if the signal
changes to a 5V pulse signal, replace the T high voltage supply board.
If there is no problem with the signal lines, replace the drum if the sensitivity does
not recover even when the drum is not exposed to light.
FT5535/4527/4522 6-4 FSM