The FANUC A20B-8100-0136 is an LCD-mounted main PCB with PMC-SA5 for compatible FANUC Series 21i/210i Model A CNC systems. It provides the main hardware platform for configured 21i-MA and 21i-TA controls used on CNC machine tools.

This motherboard accepts system components such as the CPU card, servo card, graphics card and SRAM, DRAM or FROM memory modules. It is not a standalone CPU card, and the installed card and memory configuration must match the original CNC system.

A20B-8100-0136 Product Information

Series 21i-A Mainboard Architecture

The A20B-8100-0136 forms the main interconnection platform for the 21i-A control. Depending on the machine-tool configuration, plug-in CPU, servo and graphics cards plus system-memory modules are installed on the board. A bare motherboard therefore does not constitute a complete CNC control, and included modules should always be confirmed from the quotation or product photographs.

PMC-SA5 and PMC-SA1 Versions

A20B-8100-0136 is the PMC-SA5 version. It should not be confused with A20B-8100-0137, which is the related Series 21i/210i Model A motherboard with PMC-SA1. Similar appearance does not confirm interchangeability because the PMC specification, hardware revision, software and installed option cards may differ.

Replacement and SRAM Backup

Before replacement, back up SRAM data, CNC parameters, programs, offsets, pitch-error compensation, PMC data and machine-builder files. Confirm the complete PCB number, slash revision, CPU card, servo card, graphics card, memory modules, boot software and SRAM checking method. Incorrect restoration or an ECC/parity mismatch may cause startup alarms or loss of machine data.

Related resources: FANUC CNC main boards and PCBs and FANUC CNC board repair services.