Brother IntelliFax-3550 Service Manual page 69

1.15 Main PCB
(1) Remove the three screws from the interface plate.
(2) Pull out the interface plate to the rear of the machine and take out the main PCB from
the shield bracket.
(3) Slightly lift up the main PCB and disconnect the following ten harnesses:
• Main motor harness (4-pin), P9
• Scanner motor harness (6-pin), P10
• Main–low-voltage harness (5-pin), P7
• Main-panel harness (5-pin), P5
• Solenoid harness (2-pin), P8
• Fan 2 harness (2-pin), P18
• Speaker harness (2-pin), P16
• Hook switch harness (2-pin), P11
• Main-NCU harness (12-pin), P6
Main-NCU harness (6-pin), P6 (on the European and Asian versions only)
• Main-sensor harness (11-pin), P4
Main PCB
Interface plate
Main cover
(placed upside
down)
Centronics parallel
interface connector
(Rear)
Main motor harness
Scanner motor harness
Solenoid harness
Speaker harness
Hook switch harness
Interface plate
P9
P7
P10 P5
P8
P18
P4
P16
P11 P6
Relay PCB
IV – 19
Relay PCB
Main–low-voltage harness
Main-panel harness
Fan 2 harness
Main-sensor harness
Main-NCU harness
P13
Shield bracket