Brother PR600II Service Manual page 304

Failure Investigation for Electronic Parts The hoop sensor does not function normally.
Is the resistance between each terminal at
both ends 1Ω or below when both ends of the
FFC (SML2CD-C) are removed from the PCB?
Is the resistance between each terminal at
both ends 1Ω or below when both ends of the
FFC (SML2CD-Y) are removed from the PCB?
Does the hoop sensor's lever rotate smoothly
and return to the stopper by the force of its
spring when pressed with fingers?
Does the resistance between pins 1 and 2, and 2
and 3 of the connector vary from approximately 0
to 1.2kΩ, respectively, as the lever rotates, when
the hoop sensor's lead is removed from the hoop
sensor PCB? Is the resistance between pins 1
and 3 approximately 1.2kΩ?
Does the machine function normally when the
hoop sensor PCB is replaced with a reliable one?
Does the machine function normally when the X
area sensor PCB is replaced with a reliable one?
5 - 22
From the previous page
Y
Y
Y
Y
N
N
To the next page
N
Change FFC (SML2CD-C).
N
Change FFC (SML2CD-Y).
N
Change hoop sensor and
tune it again.
N
Change hoop sensor and
tune it again.
Y
Change hoop sensor PCB.
Y
Change X area sensor PCB.