Brother PR655 Service Manual page 286

Failure Investigation for Electronic Parts
• Power supply voltage error (24V high)
• Power supply voltage error (24V low)
• Power supply voltage error (40V high)
• Power supply voltage error (40V low)
(Dialog message)
Is the power lead properly connected
to CN26 on the main PCB?
Is the voltage between pins 1 and 2, and
3 and 4 of connector CN26 on the main
PCB 38.0 - 42.0V, and 23.0 - 27.0V,
respectively, when the power is ON?
Error message
Y
Y
Change the main PCB.
5 - 31
N
Connect it properly.
N
Change the power supply
PCB unit.