FANUC A20B-2902-0390 is an Alpha power driver board / drive module used in FANUC power supply and spindle amplifier modules. It provides power-stage driving functions and is different from the main control PCB or base wiring board.

FANUC documentation lists this board in compatible Alpha PSM and SPM modules. Because it appears across several sizes and interfaces, replacement must be based on the A20B label, revision and complete A06B host number.

A20B-2902-0390 Product Information

Power Driver Function

The A20B-2902-0390 transfers drive commands to compatible power semiconductor modules. A damaged board can contribute to overcurrent alarms, missing drive output, uneven transistor switching or repeated power-module failure.

PSM and SPM Applications

In PSM assemblies, FANUC identifies A20B-2902-0390 as a driver board. In many CE-marked SPM configurations, it is installed with wiring boards such as A20B-1006-0486, A20B-1006-0487, A20B-1006-0488 or A20B-1006-0489. The complete modules remain model-specific.

Compatibility and Revision Checks

Confirm A20B-2902-0390, its printed revision, connector layout and full A06B host model. Also verify CE status and whether the documentation specifies A20B-2902-0390 or A20B-2902-0280. Similar appearance does not establish compatibility.

Testing and Installation Notes

REACO CNC checks the label, revision, connectors, drive components, solder condition and compatible module operation where applicable. Power semiconductors and related resistors should also be checked before replacement. Qualified personnel must isolate power and discharge the DC bus fully.

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