Troubleshooting And Repair; Items To Check Before Repair; Troubleshooting Table - Oki ML420 Maintenance Manual

6.

TROUBLESHOOTING AND REPAIR

6.1

Items to Check Before Repair

(1) Check the inspection items specified in the instruction manual.
(2) Find out as many details of the trouble as possible from the customer.
(3) Inspect in the conditions as close as possible to those at the time the trouble occurred.
(4) Proceed with the repair as follows:
Check the trouble status according to Table 6.1 for the details of the trouble. Then, locate
the trouble position according to the detailed flowchart.
(5) Carry out a thorough test after the repair to check for correct functioning.
6.2

Troubleshooting Table

Status
• Power is not supplied.
• No spacing operation
Trouble upon
power on
• Homing does not end normally.
• Paper jam while paper insertion
• Smearing/Missing dots
• Faint or dark print
Trouble during
• Ribbon feed trouble
printing
• Line feed trouble
• Malfunction of switch on
• Data receiving failure
42113901TH01 Rev.3
Table 6.1
Trouble Contents
operation panel
Troubleshooting
Surmise of Trouble
Flowchart No.
Power Supply Board,
1
Control Board, Transformer Assy.
Space Motor, Carriage Cable,
2 Printhead.
Space Motor, Carriage Cable,
Power Supply Board,
3
Control Board, Spacing Mechanism
Pressure Roller Mechanism, Pull Up
4
Roller Cover.
Printhead, Control Board, Space
5
Motor, Carriage Cable
Printhead, Ribbon Feed Assembly,
6
Control Board
Ribbon Feed Assembly, Space
7
Motor, Control Board
LF Motor, Platen Assy, LF
8
Mechanism, Control Board
Operation Panel Board,
9
Control Board
Control Board, (RS232C I/F Board),
0
I/F Cable, Menu Setting
Oki Data CONFIDENTIAL
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