The FANUC A20B-1008-0081 is a power board used in Alpha i Series αiPS55 power supply modules. It forms part of the high-current power stage in selected 200VAC-class regenerative supplies that provide the common DC link for compatible FANUC servo and spindle amplifiers.

FANUC tables associate this board with complete modules A06B-6110-H055 and A06B-6140-H055. It operates with a separate A20B-2003-0420 driver PCB and a model-dependent control PCB. Match the complete board label and host-module number before replacement.

A20B-1008-0081 Product Information

αiPS55 Power-Stage Function

A20B-1008-0081 carries high-current power distribution within the αiPS55 and interfaces with the AC input, converter, regenerative section and common DC bus. The complete supply returns regenerative energy toward the incoming supply while supporting connected servo and spindle amplifiers.

Driver and Control PCB Matching

This board is not the separate A20B-2003-0420 driver PCB. A06B-6110-H055 uses A20B-2100-0391, with A20B-2100-0761 documented as an older control-PCB specification; A06B-6140-H055 uses A20B-2100-0390. Confirm the complete module, unit specification, PCB labels, connectors and installed power components.

Testing and Installation Notes

REACO CNC checks the label, connectors, terminals, power components, solder joints and applicable electrical functions. Power-supply alarms may also originate from the control PCB, driver PCB, IGBT modules, incoming supply, reactor, fuses, fans or connected amplifiers. Qualified personnel must isolate power and allow the DC bus to discharge before service.

Related resources: FANUC circuit boards, FANUC power supply modules and FANUC CNC repair services.