1PC USED GE FANUC A20B-3300-0170 CPU Card Tested A20B33000170 A2OB-33OO-O17O

A20B-3300-0170 | FANUC MMX CPU Module — Series 16i / 18i / CNC / Intel MMX Architecture / DRAM Expansion Slot / Model A Motherboard

MMX Architecture — A Step Up From the 486 Generation

MMX marked a significant transition in the A20B-3300 CPU module series. Earlier FANUC i-series CPU cards used Intel 486DX-based processors — capable and reliable for the time, but limited to the original x86 integer instruction set.

Intel's MMX extension introduced 57 new SIMD (Single Instruction, Multiple Data) instructions to the processor's architecture. These instructions allow the processor to execute certain calculations on multiple data points simultaneously rather than sequentially. For CNC applications, this translates into more efficient execution of floating-point-intensive operations: circular arc calculations, complex tool path interpolation, real-time programme look-ahead, and graphical rendering for the operator's display.

The A20B-3300-0170 brings this MMX-capable processing core to the FANUC Series 16i and 18i CNC platform, delivering increased computational throughput compared to 486-generation predecessors within the same physical form factor.

Key Specifications

Direct Plug-In to the 16i/18i Motherboard

The A20B-3300-0170 installs directly into the CPU card slot on the FANUC Series 16i/18i main board (motherboard). This is the same installation method as the earlier 486-generation CPU cards — the physical slot interface is consistent across the Model A generation, making the A20B-3300-0170 a direct replacement for the earlier 486DX2 CPU card in the same slot.

For maintenance purposes, this means replacing a failed CPU card requires only access to the CNC control unit's interior, no additional mounting hardware, and no changes to the wiring or other boards in the unit.

Application Scenarios

Series 18i CNC CPU failure: A FANUC 18i-MA CNC fails to complete its startup sequence. Testing isolates the fault to the CPU module. Fitting the A20B-3300-0170 restores the CNC's startup and operation. The MMX-equipped card replaces the previous 486-class module without motherboard changes.

CPU module performance refresh: A Series 16i CNC running a 486-generation CPU card is experiencing programme look-ahead limitations at high feedrates. Replacing the CPU card with the A20B-3300-0170 MMX module, along with a DRAM expansion module, increases available processing capacity and working memory for improved look-ahead buffering.

FAQ

Q1: Is the A20B-3300-0170 compatible with Series 16i-B or 18i-B (Model B) systems?

The A20B-3300-0170 is specified for the Model A hardware generation of the 16i and 18i series. Model B hardware uses a different motherboard revision with a different CPU card interface. The A20B-3300-0170 is not interchangeable with Model B CPU cards. Confirm the CNC's hardware generation from its system configuration screen before ordering.

Q2: What DRAM module fits the expansion slot on the A20B-3300-0170?

The DRAM module for the A20B-3300-0170's expansion slot is a separate FANUC A20B-3300 series memory card — the specific DRAM module part number depends on the desired memory capacity (the A20B-3300-0291 is one such option with 16MB onboard). Confirm the compatible DRAM module from the 16i/18i hardware installation documentation before ordering.

Q3: Will replacing the A20B-3300-0170 delete the CNC's programme data?

No. The CNC's programmes, tool offsets, work offsets, and machine parameters are stored in FROM (flash) and SRAM (battery-backed) memory on separate memory modules — not on the CPU card. Replacing the CPU card does not erase stored programme data, provided the memory modules and their battery backup remain intact during the replacement. Always back up all CNC data before any internal board replacement as a precaution.

Q4: What is the difference between the MMX CPU module and the 486DX2 CPU module for the 16i/18i?

The 486DX2-based CPU card (such as A20B-3300-0070) and the MMX-based A20B-3300-0170 differ in processing architecture. The 486DX2 runs at 66 MHz using the standard 486 instruction set. The MMX card uses a higher-generation processor with the expanded MMX instruction set, providing greater integer throughput for the same tasks. The practical benefit in CNC operation is faster execution of interpolation and look-ahead calculations, enabling smoother high-feedrate contouring.

Q5: Can the A20B-3300-0170 be installed in a 21i-A CNC?

The A20B-3300-0170 is confirmed for 16i and 18i series systems. The 21i series is a separate CNC model within the i-generation family — confirm compatibility for 21i-A systems from the 21i hardware manual before fitting the A20B-3300-0170 in a 21i application.