Oki MC770 series Maintenance Manual - page 189

45376001TH  Rev.1 

188 /

Oki  Data  CONFIDENTIAL

7. Troubleshooting and repair procedure

Check item

Check work

Action to be taken 

at NG

(14-2-2) Check the system connection

Check the system 

connection from 

the PU board to the 

option tray board 

(GOH-11 PCB).

Check that the cable between the PU board 

option connector 

 to the option tray board is 

normally connected.

  Correct  the 

connections.

  Square  connector 

connecting the 

option tray unit to 

the printer.

Check if any foreign material exists in the 

connecting portion of the square connector.

    Remove  the 

foreign material.

Square connector 

connecting the 

option tray unit to 

the printer.

Is the terminals of the square connector 

damaged?

Replace the 

connector.

(14-2-3) Check the control signals.

Check the control 

signal that is output 

from the PU board to 

the option tray board 

(GOH-11 PCB).

Check the control signal that is output from the 

PU board option connector 

. 

Pin-5: TXD (PU   2nd) 

Pin-3: RXD (2nd   PU) 

Replace the PU 

board.

7.5.4. (15) LED head cannot be recognized. (error code CE82, CE83, CE84, CE85)

(15-1) Service call CE82 to CE85 (LED HEAD Missing)

Check item

Check work

Action to be taken 

at NG

(15-1-1) Check the system connection

Connecting condition 

at the PU board 

connector and at the 

head connector.

Check the connecting condition of the FFC by 

the visual inspection.

  Correct  the 

connection 

to the normal 

connecting 

condition.

Head  FFC   

Remove the head FFC from the printer. Check 

if any open-circuit or peeling-off of sheath has 

occurred or not throughout the cable.

Replace the 

head FFC or the 

PU board. 

Conduction of the 

fuse on the PU 

board.

Check that 5V appears across the capacitor 

CP8. (Refer to section 7.6.) 

Check if the fuses F8 and F9 are not open-circuit 

or not.

Replace the PU 

board.