3 ] Malfunction - Brother FAX-2820 Service Manual

[ 3 ] Malfunction
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
M-2 No DC power supplied
Possible cause
AC power
supply
Wiring, DC
load
Low-voltage
power supply
PCB
*1
PCB +lead pin
Main CN12-6
CN12-8
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?
Check
Step
1 Is AC power supplied
between connectors CN1-L
and CN1-N when the
power plug is plugged into
the outlet?
2 Turn on the power switch.
Measure the voltages
between the terminals. Do
the measured voltage
satisfy the prescribed
valued in the table below?
3 Refer to the chart * 1
below.
- lead pin
CN12-9
CN12-9
Result
No Inform the user that the correct
voltage is not supplied at the
outlet.
No Plug the power cord securely
into the outlet.
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.
Yes Replace the AC power cord.
Result
No 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.
Voltage
Approx. 24V
Approx. 5V
9 -2 2
Remedy
Remedy
Confidential