Brother NV4000D Service Manual page 366

Failure Investigation for Electronic Parts Error is displayed
5 - 40
"F04" is displayed
Are the foot controller jack assy.
lead wires broken?
N
Is the foot controller jack assembly
correctly connected to the panel
PCB assembly (CN9)?
Y
When the foot controller is replaced
with a new one, does it work
correctly?
Y
Replace the foot controller.
Y
Replace the foot controller
jack assy.
Correctly connect the foot
N
controller jack assembly to the
panel PCB assembly (CN9).
N
Replace the panel PCB
assembly.