Mother Board A20B-2000-0180 A20B20000180 A2OB-2OOO-O18O

A20B-3300-0293 | FANUC 486 CPU Module — 16MB DRAM / A20B-3300-029x Family / Plug-In Processor Card / FANUC CNC

A20B-3300 — The CPU Module Series

The A20B-3300 series is FANUC's family of plug-in CPU modules — the processor cards that provide the central processing capability in FANUC CNC main boards. The series spans multiple generations of CNC platforms and processor architectures:

The A20B-3300-029x family occupies the 486-era processor range:

The 029x family represents the Intel 486 generation of FANUC's CNC processing — a significant leap from the 486's predecessors, delivering the processing power needed for the first-generation i-series CNC platforms.

Key Specifications

Plug-In Architecture — The Service Benefit

The A20B-3300-0293 plugs into a defined socket on the CNC main board — a modular design that separates the processor module from the main board. This provides:

Independent replaceability: When the CPU module fails, only the module is replaced — the main board, memory modules, and option cards are undisturbed.

Non-invasive data preservation: Replacing the A20B-3300-0293 does not affect CNC parameters or part programmes — these reside in SRAM and FROM modules on or near the main board, not in the CPU module itself.

Application Scenarios

CNC processor module fault: A FANUC CNC develops persistent boot failures or CPU-level alarms. All memory modules test correctly. The A20B-3300-0293 processor module is identified as the fault. Replacement restores normal CNC boot and operation.

CNC electronics maintenance: An ageing FANUC i-series CNC undergoes electronics refurbishment. The A20B-3300-0293 CPU module is replaced to reset the processor's service life.

FAQ

Q1: What CNC systems use the A20B-3300-0293 486 CPU module?

The A20B-3300-029x family serves FANUC i-series CNC platforms from the 486 processor era. Adjacent members (0290, 0291) confirm compatibility with Series 15i, 16i, 18i, and 21i platforms in their A and B hardware generations. Confirm the specific CNC model from the host board's hardware documentation.

Q2: How does A20B-3300-0293 compare to the Pentium-class modules (A20B-3300-0312/0313)?

The 029x family uses Intel 486-class processors. The 031x family uses Intel Pentium-class processors. The Pentium offers approximately double the instruction throughput per clock via its superscalar dual-issue pipeline, wider memory bus bandwidth, and significantly faster floating-point performance. The two module generations serve different CNC hardware generations and are not interchangeable.

Q3: Does replacing A20B-3300-0293 require any CNC reconfiguration?

No. CNC parameters, PMC ladder, and part programmes reside in SRAM and FROM modules — separate from the CPU module. Replacing A20B-3300-0293 does not affect these stored data. The CNC boots from FROM and reads parameters from SRAM after the new module is fitted.

Q4: What is the 16MB DRAM used for in a 486-era CNC?

The 16MB DRAM on A20B-3300-0293 is the processor's working memory. At boot, the CNC copies its system software from FROM into this DRAM for fast execution. All runtime variables, look-ahead buffer data, axis state information, and active programme data reside in this DRAM during machine operation. The 16MB capacity is matched to the software footprint of 486-era FANUC CNC software versions.

Q5: Is repair or exchange available for A20B-3300-0293?

FanucWorld lists A20B-3300-0293 as in stock for direct sale. The board is also noted as "Core Exchange: Not accepting at this time; Repair: Not offering at this time" on FanucWorld — direct board replacement is the recommended service approach for this module.