Brother NV-10A Service Manual page 186

Failure Investigation for Electronic Parts Error is displayed
Is the voltage between pins 3 & 4 of
CN5 on the main PCB assy. 30 V DC?
5 - 24
"F8" is displayed
Y
Replace the main PCB assy.
"F9" is displayed
Y
Replace the main PCB assy.
N
Replace the power supply assy.