MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN
SERVICE MANUAL
6-23
5. MALFUNCTIONS
When taking countermeasures for malfunctions as described in this section, check connectors
for contact failure before measuring the voltage at the specified connector pins.
M-1
No AC power supplied
Possible cause
Step
Check
Result
Remedy
Supply voltage
1
Is the correct voltage present
at the outlet?
No
Inform the user that the
correct voltage is not supplied
at the outlet.
Power plug
2
Is the power cord securely
plugged into the outlet?
No
Plug the power cord securely
into the outlet.
Fuse (F1, F2)
3
Is the fuse blown?
Yes
If the fuse blows again
immediately after replacing
the low-voltage power supply
PCB, check that there is not a
short circuit somewhere in the
AC power supply line.
Wiring
4
Unplug the power supply plug.
Is there a broken wire between
the AC input connector of the
low-voltage power supply and
the power plug?
Yes
Replace the AC power cord.
M-2
No DC power supplied
Possible cause
Step
Check
Result
Remedy
AC power
supply
1
Is AC power supplied between
connectors CN1-L and CN1-N
when the power plug is
plugged into the outlet?
No
Follow the same check
procedure of M-1 “No AC
power supplied”.
Wiring, DC load
2
Turn on the power switch.
Measure the voltages between
the terminals. Do the
measured voltage satisfy the
prescribed valued in the table
below?
Yes
Turn off the power switch,
reconnect the connector and
turn the power switch on
again. If the protector circuit
is activated, check the
connector, the wiring from the
connector, and the DC load.
Low-voltage
power supply
PCB
3
Refer to the chart *1 below.
No
Replace the low-voltage
power supply PCB.
*1
PCB
+lead pin
- lead pin
Voltage
Engine CN8-3
CN10-6
CN8-2
CN10-5
Approx. 24V
Approx. 3.3V
Summary of Contents for DCP-8020
Page 264: ...CHAPTER 7 MAINTENANCE MODE 7 6 Fig 7 3 l m a b c d e f g h i j k ...
Page 335: ...APPENDIX 4 CIRCUIT DIAGRAMS A 50 Appendix 4 1 Main PCB Circuit Diagram 1 6 ...
Page 337: ...APPENDIX 4 CIRCUIT DIAGRAMS A 52 Appendix 4 3 Main PCB Circuit Diagram 3 6 ...
Page 339: ...APPENDIX 4 CIRCUIT DIAGRAMS A 54 Appendix 4 5 Main PCB Circuit Diagram 5 6 ...
Page 341: ...APPENDIX 4 CIRCUIT DIAGRAMS A 56 Appendix 4 7 Driver PCB Circuit Diagram ...
Page 343: ...APPENDIX 4 CIRCUIT DIAGRAMS A 58 Appendix 4 9 Engine PCB Circuit Diagram 2 2 ...
Page 345: ...APPENDIX 4 CIRCUIT DIAGRAMS A 60 Appendix 4 11 NCU PCB Circuit Diagram Europe ...
Page 347: ...APPENDIX 4 CIRCUIT DIAGRAMS A 62 Appendix 4 13 NCU PCB Circuit Diagram Oceania ...