Brother 431B Sewing Machine User Manual


 
8. ELECTRIC MECHANISM
Erro
r status #1 The power indicator does not light when the power is turned on.
Probable causes Check/ repair/ adjust Parts to be replaced
5. Power supply circuit board
defective
• Separate P4 (ACIN) connectors on the
power supply circuit board, and then
measure the resistance between the
following pairs of pins, pins 1 and 4 and
pins 2 and 4, in the connector on the
cable.
KE-430B, 430C series
178
If the resistance is in both cases, the
power supply circuit board is not defective.
• Measure the resistance between pins 1
and 2.
If there is no short, the power supply
circuit board is not defective.
• Rejoin P4 (ACIN) connectors on the
power supply circuit board.
Separate P9 (POWER) connectors on the
main circuit board, turn on the power, and
measure the voltage across pins 1 and 3
in the connector on the cable.
If it is + 5V, the power circuit board is not
defective.
After measurement, turn off the power,
wait at least 5 minutes, and then rejoin P9
connectors.
Power supply circuit
board
6. Main circuit board defective • With P9 (POWER) connectors plugged in
on the main circuit board, turn on the
power, and measure the voltage across
pins 1 and 3 in the connector on the cable.
If it is + 5V, the power circuit board is not
defective.
After measurement, turn off the power.
Ma
in circuit board
Check that P8 (PANEL) connectors of the
main circuit board and P1 (PANEL)
connectors of the panel circuit board are
plugged in.
Panel circuit board
Panel cord
7. Panel circuit board defective
<KE-436B, 436C>
• Check that P20 (RSPORT) connectors of
the main circuit board and P5 (DRV)
connectors of the panel circuit board are
plugged in.
Panel circuit board
3634Q
3635Q
Error status #2 Error code appears on the display window when the power is turned on.
Probable causes Check/ repair/ adjust Parts to be replaced
1. Cooling fan defective when
the error code E-70 appears
on the display window.
([E.c1] KE-436B, 436C)
a. Check threads are not tangled in the
cooling fan.
b. Check P10 (FAN) connectors are
securely plugged in on the main circuit
board.
DC fan motor assembly