FANUC A20B-0008-0241 is a legacy spindle orientation PCB used in compatible FANUC AC spindle servo systems. FANUC documentation identifies it as the Orientation B / BS board for position-coder feedback with a two-stage speed-change gear spindle.

The board processes spindle-position feedback so the machine can stop at a repeatable angular position for automatic tool changes and other orientation-dependent CNC cycles. It is an option or daughter board, not a complete spindle amplifier.

A20B-0008-0241 Product Information

Position-Coder Spindle Orientation Function

When the CNC requests spindle orientation, commonly through an M19 command, the board uses position-coder feedback to control the final angular stop. Correct operation depends on the complete spindle drive, motor, position coder, gearing, wiring, parameters and machine-builder logic.

Exact-Model and Compatibility Checks

Match the complete A20B-0008-0241 marking and original orientation-unit number. Do not substitute A20B-0008-0240 merely because it is also a position-coder board: the 0240 belongs to Orientation A / AS. A20B-0008-0030 and A20B-0008-0031 use magnetic-sensor configurations and are not equivalent.

Testing and Installation Notes

REACO CNC checks the board marking, PCB condition, components, connectors, position-feedback circuit and orientation signals, with repeatability testing on a compatible setup when available. Before replacement, photograph wiring and record switches, jumpers and adjustment settings. Isolate power, allow the DC bus to discharge and use ESD-safe handling.

Related resources: FANUC CNC and robot parts and FANUC spindle drive and PCB repair service.