The FANUC A20B-8003-0012 is a 24VDC display power distribution and interface PCB used in selected FANUC CNC display and control assemblies. It supplies auxiliary power to the LED display and cooling fan and provides a connection path for the CNC memory-backup battery.

Parts suppliers may call it an inverter board, high-voltage board or display adapter. Here, “inverter” refers to the display/backlight circuit—not a servo or spindle power module. Common boards carry revision A20B-8003-0012/02A; match the complete number printed on the original PCB.

A20B-8003-0012 Product Information

LED Display and Auxiliary Power Function

A20B-8003-0012 routes 24V auxiliary power inside the CNC display assembly. Depending on the host, a fault may contribute to a dark or unstable display, an inactive cooling fan or an interrupted battery-feed path. Because other components can cause similar symptoms, check the power supply, cables, display and battery before replacement.

Compatibility and Board Identification

This PCB appears in selected FANUC CNC display/control configurations, including equipment from the 0i-D generation. Compatibility cannot be determined from the A20B family alone. Compare A20B-8003-0012, the suffix such as /02A, connector layout, mounting points, host A02B unit number and machine configuration. Do not substitute A20B-8003-0010, -0011, -0013 or a visually similar board without documented approval.

Testing and Installation Notes

REACO CNC checks the PCB label, connectors, components, 24V power path and applicable display, fan and battery interfaces before shipment. Isolate machine power and use ESD protection during installation. Back up CNC parameters, programs, offsets and PMC data before disturbing a memory-backup connection.

Related resources: FANUC CNC circuit boards, FANUC CNC controls and FANUC CNC repair services.