Brother T-8421D Instruction Manual page 110

Code
E410 Communication error with panel occurred when
power was turned on.
E422 An error occurred while reading from USB
media.
E424 Not enough free space in the USB media.
E425 An error occurred while writing to USB media.
E440 Data could not be written to the backup
memory (main internal P.C. board).
E441 Data could not be read from the backup
memory (main internal P.C. board).
E442 Back up memory (main internal P.C. board)
data was abnormal, so settings were initialized.
E450 Model selections could not be read from
machine head memory (internal panel).
E451 Data backup cannot be written to machine head
memory (internal panel).
E452 Machine head memory is not connected.
Software-related errors
Code
E582 A memory switch version updating error was
detected (including specification mismatch).
E583 A parameter version updating error was detected
(including specification mismatch).
P.C. board-related errors
Code
E700 Abnormal rise in power supply voltage was
detected when power was turned on.
E701 Abnormal rise in sewing machine motor power
supply voltage was detected.
E705 Abnormal drop in power supply voltage was
detected.
E709 Power supply signal could not be detected
when power was turned on.
E710 Abnormal sewing machine motor current was
detected.
E740 Fan motor does not operate.
Cause
Cause
Cause
Remedy
Turn off the power and check the connection of
connector CN6.
• Press the RESET key.
• Check the files in the USB media.
• Press the RESET key.
• Increase the amount of free space.
• Press the RESET key.
• Use the specified USB media.
Turn the power off and then back on again.
Turn the power off and then back on again.
Turn the power off and then back on again.
Turn off the power and check the connection of
connector P3.
Turn off the power and check the connection of
connector P3.
Turn off the power and check the connection of
connector P3.
Remedy
Turn the power off and then back on again.
Turn the power off and then back on again.
Remedy
Turn off the power and check the power supply
voltage.
• Turn off the power and check the power
supply voltage.
• Turn off the power and check the connection
of connector P4.
Turn off the power and check the power supply
voltage.
Turn the power off and then back on again.
Turn off the power and check the connections of
the 4-pin sewing machine motor connector.
• Turn off the power, and then check if the
cooling fan is blocked with scraps of thread.
• Turn off the power and check the connection
of connector CN3.
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