Brother International DCP 8040 Service Manual - Page 226

Malfunctions

Page 226 highlights

MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN SERVICE MANUAL 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 Supply voltage Power plug Fuse (F1, F2) Wiring Step Check 1 Is the correct voltage present at the outlet? 2 Is the power cord securely plugged into the outlet? 3 Is the fuse blown? 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? Result No No Yes Yes Remedy Inform the user that the correct voltage is not supplied at the outlet. Plug the power cord securely into the outlet. 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. Replace the AC power cord. M-2 No DC power supplied Possible cause AC power supply Wiring, DC load Step 1 2 Check Is AC power supplied between connectors CN1-L and CN1-N when the power plug is plugged into the outlet? Turn on the power switch. Measure the voltages between the terminals. Do the measured voltage satisfy the prescribed valued in the table below? Low-voltage 3 power supply PCB *1 PCB +lead pin Engine CN8-3 CN10-6 Refer to the chart *1 below. - lead pin CN8-2 CN10-5 Voltage Approx. 24V Approx. 3.3V Result No Remedy Follow the same check procedure of M-1 "No AC power supplied". 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. No Replace the low-voltage power supply PCB. 6-23

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MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN
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