Electrical Section - Brother BES-1240BC Instruction Manual

Chapter 12 Trouble Shooting

Electrical Section

Cautions
• Be sure to turn off the power of the machine and unplug the power cord before checking cable
connections.
• When you check connection of the cables as instructed in this manual, also check connection and
continuity between connectors.
• Carry out items described in the "Measures" section in order of appearance.
• Some checks and replacement works can be conducted only by repair people. In such cases,
contact your dealer.
Symptom
The machine does not operate even
if the power is turned on.
The machine does not operate even
if the power is turned on.
The message, "Release stop SW to
operate!", is displayed on the panel.
• The message, "Is the presser foot
removed?", is displayed on the
machine controller when the power
is turned on.
• The red LED of head 2 or 4 does
not light and the presser foot
remains lowered.
An overtravel error occurs.
The needle stop position error oc-
curs.
258
• Is the power cord of the machine plugged in?
Plug in the power cord.
• Is the connector at the rear of the control box connected?
Connect it after checking the connector number and the harness number.
• Is the connector in the control box or the power supply base connected?
Connect it after checking the types and colors of the connectors.
• Is fuse F1 or F2 on the power PCB in the power supply base blown?
Replace the fuse with a new one. If the fuse is blown again,
something is faulty. Check to see if the wiring is correct. Replace the
control box with a new one.
• Is the stop switch turned on?
Reset the stop switch.
• Is the retract bed sensor adjusted properly?
Adjust the retract bed sensor of the faulty head. (Refer to "Replacing
the retract bed sensor PCB".)
• Refer to the block diagram showing cable connection and check
connection from the retreat bed sensor to the main PCB.
• Check to see if the frame type is set to every other head with the
machine controller.
• Is the frame within the cap frame area?
Move the frame within the cap frame area and turn on the power.
• Check to see if the signal of the X area sensor turns ON and OFF in
PORT test mode.
When the signal does not change, refer to the block diagram showing
the cable connections and check to see if connection from the X area sensor
to the main PCB is proper. Replace the X area sensor with a new one.
• Is the pulley manually turned and out of the stop angle?
Turn the pulley, adjust the needle at the stop position, and reset
the error.
• Check the signal of the stop position sensor in the encoder test mode.
Refer to the adjustment or cable connection block diagram and
check connection from the needle position detention sensor to the main
PCB. Replace the needle position detection sensor with a new one.
BES-940BC • BES-1240BC
Measures