A20B-3300-0471 Fanuc PCB Board A20B33000471 A2OB-33OO-O47I

A20B-3300-0471 | FANUC B3 Generation CPU Module — 128MB DRAM / Series 16i-B / 18i-B / 21i-B / Full B-Generation Memory

B3 — Full Memory for the i-B Generation

The A20B-3300-0471 is the maximum-memory CPU module for the FANUC i-B generation CNC platforms. At 128MB DRAM, it doubles the working memory of the B2 module (A20B-3300-0470) and provides eight times the memory of the original Pentium MMX modules that first served these platforms.

This 128MB capacity is not a luxury — it is the appropriate specification for Series 16i-B, 18i-B, and 21i-B CNC systems that are:

Fully optioned: Advanced software options including AICC (AI Contour Control), 5-axis transformations, servo optimisation, graphic check, and others each add to the CNC software footprint. A fully-optioned i-B CNC benefits from the 128MB B3 module's memory headroom.

PC function enabled: The i-B series CNC supports an embedded PC function for custom HMI applications, data collection, and DNC. PC function software runs within the same working memory as the CNC kernel — 128MB provides sufficient space for both.

Serving the 21i-B platform: The 21i-B is a more complex platform than the 16i-B/18i-B. The B3 is the only confirmed CPU module covering all three: 16i-B, 18i-B, and 21i-B. The B2 (0470) is confirmed for 16i-B and 18i-B only.

Key Specifications

B2 vs B3 — When to Choose Each

The choice between B2 (A20B-3300-0470) and B3 (A20B-3300-0471) depends on the installed CNC configuration:

For straightforward replacement: match the installed module's designation. A CNC configured with a B2 was validated with 64MB. A CNC with a B3 uses the full 128MB. Substituting without design review may work in one direction (B3 in a B2 slot, effectively providing more memory than needed) but not the other (B2 in a B3 slot would provide half the expected memory).

Application Scenarios

21i-B CNC CPU module fault: A FANUC Series 21i-B machining centre develops CPU-level faults. The A20B-3300-0471 is confirmed as the correct B3 module. Replacement restores 128MB CPU processing.

16i-B CNC memory upgrade: A Series 16i-B CNC currently running a B2 module (64MB) is upgraded to B3 (128MB) when additional software options are installed that require more working memory.

FAQ

Q1: Is A20B-3300-0471 (B3, 128MB) compatible in a 16i-B main board slot designed for the B2 (64MB)?

The B3 at 128MB provides more memory than the B2. In most cases, the B3 is a compatible replacement in a slot designed for the B2 — the larger memory does not cause compatibility issues. The CNC will benefit from additional working memory. Confirm from the FANUC 16i-B hardware documentation if any minimum or maximum memory constraint applies.

Q2: What is the main advantage of B3 (128MB) over the earlier Pentium MMX modules (16–32MB)?

The B3 provides 4–8× more working memory than the Pentium MMX generation (16MB or 32MB). This allows fully-optioned CNC configurations, PC function applications, and complex programme look-ahead processing to operate without memory pressure — delivering more stable and consistent CNC performance across the option set installed.

Q3: Does replacing A20B-3300-0471 affect CNC parameters or programmes?

No. CNC parameters and programmes reside in SRAM and FROM modules separate from the CPU module. Replacing A20B-3300-0471 does not affect stored data. After fitting the replacement, the CNC boots from FROM and reads parameters from SRAM automatically.

Q4: Is A20B-3300-0471 also used in the Series 21i-A (Model A), or only 21i-B?

The B3 designation specifically identifies the B-generation hardware platform. The 21i-A (Model A) used different CPU module specifications from the 21i-B. A20B-3300-0471 is confirmed for the B-generation (21i-B) — not the A-generation (21i-A). Confirm from the hardware documentation if the installed system is 21i-A or 21i-B before ordering.

Q5: What suppliers and warranty terms are available for A20B-3300-0471?

Multiple FANUC specialists confirm availability: DNC Electronics (direct supply and exchange, 16i-B/18i-B stock maintained), fanuc-controller.com (12-month warranty), Industrial Automation Co (in-stock), FanucWorld (new/refurbished/repair). MRO Electric offers 2-year warranty on repaired units. Core exchange is available through MRO Electric.