FANUC A20B-1003-0920 is a 16-bit serial spindle control PCB used as the upper control board in compatible A06B-6063-H2xx AC spindle servo units. It supports serial communication and control between the FANUC CNC and spindle drive.

This is a replacement PCB rather than a complete spindle amplifier. Confirm the full board revision, spindle-unit model and installed ROM because A20B-1003-0920 revisions are not automatically interchangeable.

A20B-1003-0920 Product Information

Serial Spindle Control Function

The A20B-1003-0920 processes serial spindle commands and communicates status between the CNC and spindle amplifier. It works with the drive power circuitry, feedback devices and parameters to regulate spindle operation. Orientation, rigid-tapping and positioning functions depend on the complete system configuration.

Drive Model, ROM and Revision Checks

Match the revision printed after A20B-1003-0920 and verify the complete A06B-6063-Hxxx drive number, including any # suffix. Compare the ROM, connectors, switch positions, companion lower board and optional daughter boards. Similar A20B-1003 PCBs should not be selected by appearance alone.

Testing and Installation Notes

REACO CNC checks the marking, components, connectors, ROM, display section, serial communication and spindle operation as applicable. Documented diagnostic rails are +24V (+20 to +26V), +15V and −15V (±4%), and +5V (±2%); these are service test values, not an external supply specification. Back up spindle parameters and record switch positions before replacement.

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