Oki C844 / C834 / ES8434 Series Manual

PARTS REPLACEMENT

This section describes the procedures for removing and reassembling of assemblies and units in the field.
The procedures provided this section are for parts replacement. Basically, assembly procedures are in reverse order from disassembly.
Part's Numbers (①, ②, . ..etc) in this manual are not equal to Part's Numbers in the related drawing (for the Disassembly Drawing and the RSPL).

Notes for Replacing of Parts

1. Before disassembling or reassembling the Duplex unit from/to the printers, turn off the printers in which they are attached, remove them. And before to replacing of parts, unplug the AC cord and all interface cables.
   1. Be sure to use the following procedure to unplug the AC Cord:
      1. Keep pushing the Power Switch over 1min, and check the LED Lamp lights-out.
      2. Pull out the AC Plug of the AC cord from the AC power source.
      3. Unplug the AC cord and all interface cables.

Electric shock hazard.
Pull out the AC cord from the printer. Because, in the case of the AC cable connected to the printer, some circuits are active even if the printer's status is ' Power-Off '.
When replacing the low-voltage power supply, due to potential electric shock. So, wear insulated gloves or be careful not to touch the conductors or terminals of the power supply directly.
After the AC cord is unplugged, the capacitor may take about one minute to discharge completely, or could not discharge due to PCB breakdown. Use caution about electric shock.

2. Be sure to use the following procedure to reconnect the printer:
   1. Connect the AC cord and the interface cable to the printer.
   2. Insert the AC plug into the AC power source.
   3. Turn on the printer (Push the power switch between about 1min,), and the LED Lamp lights.

2. Do not disassemble the Duplex unit so long as they operate properly.
3. Determine the ranges of disassembly according to the purposes of the operations for which the disassembly is done, so as not to do more disassembly than is necessary.
4. Use designated maintenance tools.
5. Follow disassembly steps in the orders specified; damage to parts may result.
6. It is advisable to place and fix temporarily small parts that tend to get lost, such as screws and collars, to their original positions.
7. Do not use the gloves that be easily charged the static electricity in the case of to touch the micro processing unit, ROM, RAM, IC, circuit board, and etc.
8. Do not put on the printer's mainbody, floor and etc directly for the printed board.

Maintenance Tools:
Table 1 shows the tools necessary to replace printed-circuit boards and units:
Table 1: Maintenance Tools

No.	Maintenance Tool		Q'ty	Use
1		No. 2-200 screwdriver with magnetic tip	1	3 to 5mm Screws
2		Screwdriver No. 3-100	1
3		Digital multimater	1
4		Pliers	1

Parts Replacement

This Section contains the parts replacement for parts and assemblies.

Option Tray

1. Remove the four Shoulder-Lock ① and remove the four Joint ②.
2. Remove the Mainbody of printer ③, and remove the cassette ④ from the Option Tray Unit.

Option Tray Unit

1. Remove the one screw(silver) ① and the one screw(black) ② to detach the Cover-R ③.
2. Remove the one screw(silver) ④ and the one screw(black) ⑤ to detach the Cover-L ⑥.
3. Remove two screws(silver) ⑦ to detach the Cover-F ⑧.
4. Remove seven screws(silver) ⑨ to detach the Plate-Top-OP ⑩, and disconnect cables those are connected to the Board Assy.-GOH ⑫.
5. Remove two screws(silver) ⑪ to detach the Board Assy.-GOH ⑫.
6. Remove two screws(silver) ⑬ to detach the Sensor Assy-OPT ⑭. And then, detach the Spring ⑮.
7. Remove four screws(silver) ⑯ to detach the Motor-Assy ⑰.
8. Remove two screws(silver) ⑱ to detach the Connecor ⑲ and the Cord ⑳ from the Motor-Assy ⑰.
9. Remove two screws(silver) to detach the Motor-Pulse and the Cord from the Motor-Assy ⑰.
10. Remove a screw(black) to detach the Lever-paper-size.
11. Remove a screw(silver) to detach the Plate-FG, Switch-Push and the Cord.
12. Remove four screws(black) to detach the Feeder-Assy, and detach the Roller-Feed and the Roller-Pick-Up. And then, detach the Spring.
13. Remove a screw(silver) from the Feeder-Assy to detach the Plate-FGClutch.
14. Remove a E-ring and disconnect the cable from the Clutch-Hop-OP to detach the Clutch-Hop-OP.
15. Remove a E-ring from the Feeder-Assy to detach the Clutch-Feed-OP.
16. Remove a Pin and a Gear to the same direction of to remove of the Roller-Feed from the Shaft of the Feeder-Assy.
17. Remove the Shaft from the Feeder-Assy to detach the Frama-AssyPickup.
18. Remove two screws(Black) to detach the Connector and the Cord.

Paper Feed Roller (for the Option Tray Unit)

In the case of failures occur with frequently the paper feeding arter the cleaning of Paper Feed Rollers (Roller-Feed and Roller-Pick-Up) and the Reard Roller, replace of these rollers.

Note!
These three Paper Feed Rollers should be replaced at the same time.

1. Shut down the Printer, and remove the paper cassette from it.
   
2. Remove these two feed rollers from the each shaft with opening the their stopping tab to outside from each shaft.
   
3. For the paper cassette, push two tabs of the Retard Cover in the direction of the arrow, and open the Retard Cover by rotation to the back of the paper cassette.
   
4. Remove the Retard Roller Assy in the direction of the allow. And then, the Spring Retard is removed with it.
   
5. Clear the paper feed roller counter of the tray whose paper feed rollers were replaced.
   From [Admin Setup] - [Others Setup] - [Paper Feed Roller Counter Clear], select the tray whose paper feed rollers were replaced and press the <ENTER> button.

[Note for assembling of the feed roller]

1. Make sure to assemble with twirling the new Roller-Pick-Up (with Gear) to the shaft of the back side of the printer's main body.
   
2. Make sure to assemble with twirling the new Roller-Feed (without Gear) to the shaft of the front side of the printer's main body.
   Check these rollers without moving along each shaft.
   

[Note for assembling of the Retard Roller Assy.]

1. Set the Spring Retard to the part of Boss of the back face of the Retard Roller Assy, and push the each parts of bearing of the Retard Roller Assy to corresonding shaft from the obliquely downwoard.
   
2. Check the Retard Roller Assy. can be moved with smoothly centering around the shaft and the Retard Roller can be rotated. And, close the Retard Cover.
   

Note!

• The descriptions in this manual are subject to change without prior notice.
• In preparing the document, efforts have been made to ensure that the information in it is accurate. However, errors may be crept into the document. Oki Data assumes no responsibility for any damage resulting from, or claimed to be the results of, those repairs, adjustments or modifications to the printers which are made by users using the manual.
• The parts used for the printers are sensitive and, if handled improperly, may be damaged. It is strongly recommended that the products are maintained by maintenance men registered with Oki Data.
• The maintenance men should be discharged the static electricity befor the starting meintenance.