A20B-3400-0020 Fanuc PCB Board A20B34000020 A2OB-34OO-OO2O

FANUC A20B-3400-0020

32MB SDRAM CPU Module for FANUC R-30iA Robot Controllers

Product Overview

The FANUC A20B-3400-0020 is a CPU module with 32MB SDRAM. It is commonly associated with FANUC R-30iA robot controllers, and some listings also describe it as a module mounted on a SUB CPU board.

That places it in the processor side of the controller rather than in the servo amplifier, display, or memory-only board class.

This model is best described as a robot controller CPU/DRAM module rather than a general PCB.

That wording is more useful for both buyers and search indexing because it directly links the part number with its actual role: CPU-side processing and memory support inside the R-30iA control architecture.

Parameter Table

System Role

From a service perspective, A20B-3400-0020 is more than a memory card.

It belongs to the processor side of the robot controller, which means its role is tied to CPU-level board function rather than simple storage expansion. 

That makes it a much more application-specific part than a standard DIMM or SRAM board, and it is one reason exact model identification matters in robot-controller repair. 

This interpretation is supported by listings that describe it as both a CPU module and a 32MB SDRAM board for R-30iA.

FAQ

Q1: What kind of part is A20B-3400-0020?
It is a CPU module with 32MB SDRAM used in FANUC R-30iA robot controller environments.

In practical terms, that places it in the controller’s processing section rather than in the memory-only, display, or drive-amplifier categories.

Q2: Is this a robot controller part or a standard CNC memory board?
It is more accurately described as a robot controller CPU module. While it includes SDRAM, the way it is sold and identified points to a CPU-side controller role, not to a simple plug-in memory DIMM.

That distinction matters because buyers should match it as a controller CPU board, not as a generic SDRAM module.

Q3: What systems is it most commonly used in?
Listings most commonly associate it with the R-30iA platform, and one seller also notes a SUB CPU board installation context.

That gives it a clear robotics-control application rather than a broad CNC-only identity.

Q4: Why is exact matching important for A20B-3400-0020?
Because CPU modules are tied to a specific controller architecture, not just to a memory size.

A 32MB SDRAM board may sound generic, but this part is identified by its CPU role and R-30iA fit. 

In industrial repair, matching the exact part number is the safer way to preserve compatibility in the robot controller.

Q5: What should be checked before replacing it?
Technicians should confirm the exact installed part number, verify the robot controller family, and inspect the board’s mounting context within the controller.

Because this module belongs to the CPU side of the system, it is also wise to confirm that the fault truly points to the controller board rather than to surrounding power, communication, or I/O hardware. 

The final diagnostic note is practical engineering guidance based on the board’s CPU role.