The FANUC A20B-3300-0260 is a CNC CPU card for compatible FANUC i-Series Model A controls. It mounts on the main control motherboard and performs central CNC processing with the installed memory modules, system software and machine configuration.

The board is commonly identified in service listings as an MMX or Pentium CPU module for 16i/18i-family controls. FANUC documentation lists A20B-3300-0260 among Model A CPU hardware, including supported Dual Check Safety configurations. It is not a complete motherboard or servo control card.

A20B-3300-0260 Product Information

CNC Processing Function

A20B-3300-0260 executes the CNC control software and works with the motherboard, axis-control card and installed DRAM, SRAM and FROM modules. A CPU-card fault may produce startup failure, CPU alarms, repeated resets or unstable control operation, but power, memory and motherboard faults should also be diagnosed.

Compatibility and Replacement Checks

Match the complete A20B-3300-0260 number, PCB revision, motherboard, CNC series, memory configuration, software and safety options. Some service references associate it with A20B-3300-0170 or A20B-3300-0050 systems, but this does not guarantee plug-and-play substitution. Dual Check Safety installations may require the specified DRAM and matching software.

Testing and Installation Notes

REACO CNC checks the label, processor card, connectors, motherboard recognition, boot sequence and CNC startup on an applicable test system. Back up parameters, programs, offsets, PMC data, safety data and system files before removal. Replacement may require software restoration. Isolate power and use ESD protection.

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