Brother PE770 Service Manual page 187

Failure Investigation for Electronic Parts The power does not come on
Is the FFC connected correctly between the
main PCB (CN5) and the motor PCB (CN1)?
Are both connector locks applied correctly?
Is the FFC connecting the main
PCB (CN5) to the motor PCB
(CN1) free from breakage?
Is the LCD's FPC free from
breakage and is it connected to the
main PCB (CN4) correctly?
5 - 4
From previous page
Y
Y
Is the backlight turned on?
Y
Y
Does the touch panel work?
Y
Replace the LCD assy.,
or
Replace the main PCB assy.
N
Connect the FFC correctly.
N
Replace the FFC.
N
5-7 Proceed to "LCD backlight
does not come on".
N
Connect it properly.
N
5-6 Proceed to "Touch panel
does not work".