Brother 431B Sewing Machine User Manual


 
8. ELECTRIC MECHANISM
. ELECTRIC MECHANISM
-. Precautions at the time of adjustment
Pay attention to the following when opening the control box for maintenance.
Electric shock
Some large capacitors may have a high voltage remaining in them for up to 5 minutes after the power is
turned off. To prevent electric shock, wait at least 5 minutes after the power is turned off before doing the
following:
• Opening and closing the control box
• Replacing fuses
• Separating and joining connectors
• Measuring resistance
• Doing anything with a possibility of touching something inside the control box
Some adjustments require measuring the voltage while the power is turned on with the control box kept open.
In such a case, be careful not to touch any place other than that for the measurement. In addition, always
keep in mind that a high voltage remains for about 5 minutes after power is turned off.
Injury
While the power is turned on, the cooling fan of the control box operates; be careful not to get caught in it.
When separating or rejoining connectors, and measuring something, be careful not to cut your fingers on
metal parts such as heat sinks and covers.
-. Components inside the control box and the operation panel
The following are brief explanations of components inside the control box. See control circuit block diagram at
the end of this manual for the details of the connections.
Main circuit board
The main circuit board is fixed to the rear panel of the control box. This PCB serves to control machine
operation.
Power supply circuit board
The power supply circuit board is fixed at the bottom of the control box. Four fuses are mounted on this PCB.
DC fan motor
The DC fan motor serves as a fan to cool the inside of the control box. Clean the inlet filter monthly.
Conversion transformer (depending on power supply voltage specification)
The conversion transformer controls the power supply voltage to provide 220V.
Pow
er supply
circuit board
Conversion transformer
DC fan motor
Air inlet
Main circuit board
C
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3583Q
KE-430B, 430C series
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