The Power Does Not Come On - Brother PE770 Service Manual

Failure Investigation for Electronic Parts The power does not come on
When the power is turned on,
nothing appears on the LCD.
When the power is turned on, does
the buzzer sound after a while?
Is the power supply cord free from
damage and connected correctly?
Is the inlet assy. free from damage and
correctly connected to the power PCB?
Is the voltage between pins 3 & 4
and pins 5 & 4 of CN19 on the
motor PCB correct?
Pins 3 and 4
•
Pins 5 and 4
•
Is the lead wire assy. (power) free
from breakage and connected
correctly between CN3 on the main
PCB and CN19 on the motor PCB?
Replace the main PCB assy.
N
Y
Y
5 VDC
...
26 VDC
...
Y
Y
Y
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N
Connect the power supply
cord correctly or replace it.
N
Connect the inlet
correctly or replace it.
N
Replace the power supply
unit.
N
Connect it properly.
assy.
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