Sewing Lamp Does Not Light - Brother XM3700 Service Manual

Failure Investigation for Electronic Parts

Sewing lamp does not light.

When unplug the foot controller plug
from the socket of the machine, is the
voltage between pins A of the plug 108
to 132V AC? (for 120V AC countries) *
Is the LED lamp assy connector
connected to the power supply
PCB (CN2) correctly?
When disconnect the LED lamp assy
connector from the power supply PCB
(CN2), is the voltage between pins 1
and 2 at CN2 10 to 12V DC?
Replace the motor 3P supply assy.
Sewing lamp does not light
1
* Refer to Fig. 1.
*1 For 220 to 240V AC countries : 198 to 264V AC
Y
* Refer to Fig. 2.
N
* Refer to Fig. 2.
N
LED lamp lead wire
Rear cover
Power supply PCB
5 - 2
N
Replace the foot controller.
A
Fig. 1
Y
Connect it properly.
Y
Replace the LED lamp assy.
Front cover
1
CN2
Fig. 2
2