Fanuc CPU A20B-3300-0312 A20B33000312 A2OB-33OO-O312

A20B-3300-0312 | FANUC 21i-B and 210i-SB Pentium CPU Module — 16MB DRAM / A20B-3300 Series / i-B Generation Processor Card

Series 21i-B and 210i-SB — The i-B Platform

The FANUC Series 21i-B is the second hardware generation of the 21i CNC platform — a capable, compact CNC for mid-complexity machine tools. The "B" model represents a hardware step forward from the 21i-A, with the Pentium processor replacing the earlier 486 architecture.

The Series 210i-SB is a sub-variant: the "210i" designation typically identifies the FANUC Power Motion i-series or a specific machine-integrated CNC configuration, and "SB" indicates a Model SB variant. Both systems share the same A20B-3300-0312 CPU module — confirming a common processor platform across these two CNC generations.

Key Specifications

A20B-3300-031x — Pentium CPU Module Family

The A20B-3300-031x range forms a group of Pentium-class CPU modules for the i-series B generation:

Compared to the earlier A20B-3300-029x family (which used 486DX processors), the 031x Pentium boards brought the Series 21i-B's computing performance into the Pentium generation — delivering higher instruction throughput and supporting the more demanding CNC options available in the i-B platform.

Application Scenarios

21i-B CNC processor failure: A FANUC Series 21i-B CNC fails to initialise — the system stops midway through boot or presents CPU-level alarms. The A20B-3300-0312 module is identified as the fault. Replacement restores the 21i-B's processing function.

210i-SB CPU module replacement: A FANUC 210i-SB system's CPU module develops intermittent faults correlated with board temperature. The A20B-3300-0312 is replaced proactively, restoring reliable CNC operation.

FAQ

Q1: What is the difference between A20B-3300-0311 and A20B-3300-0312?

Both are Pentium CPU modules with 16MB DRAM in the 031x family. The A20B-3300-0311 serves Series 16i-B and 18i-B CNC systems. The A20B-3300-0312 serves Series 21i-B and 210i-SB. They are not interchangeable — each is matched to the specific CNC's board slot and system software for that platform.

Q2: Does the A20B-3300-0312 have more DRAM than A20B-3300-0311?

Both 0311 and 0312 carry 16MB DRAM. The A20B-3300-0313 (for 0i-C) has 32MB SDRAM (a higher capacity and a different memory technology — SDRAM versus DRAM). The memory capacity difference reflects the larger software footprint of the 0i-C generation versus the 21i-B.

Q3: Does replacing A20B-3300-0312 affect stored CNC parameters?

No. CNC parameters reside in SRAM memory modules — separate from the CPU board. Replacing the A20B-3300-0312 does not affect any stored parameter, programme, or tool data. After fitting the replacement, the CNC boots and reads parameters from the intact SRAM.

Q4: What is the Core Exchange option for A20B-3300-0312?

A core exchange means a repaired/tested replacement board is supplied in exchange for the customer's faulty board — the customer pays for the replacement and returns the faulty module. This lowers the net cost of the replacement board versus outright purchase.