Brother PE770 Service Manual page 199

Failure Investigation for Electronic Parts Lamp does not come on
When the power PCB connector is
removed from the motor PCB (CN19),
is the voltage between pins 5 & 4 of
the power PCB connector 26V DC?
Is the voltage between pins 1 & 2 of CN3
on the motor PCB or that of CN1 on the
SS PCB approximately 3 to 4V?
5 - 16
From previous page
Y
Y
Replace the main PCB assy.,
or
Replace the motor PCB assy.
N
Replace the power supply
unit.
Replace the LED lamp FL assy.,
N
or
Replace the LED lamp FR assy.