Fanuc Circuit Board A20B-2901-0941 A20B29010941 A2OB-29O1-O941

FANUC A20B-2901-0941 4MB DRAM Memory Board

The FANUC A20B-2901-0941 is a 4 MB DRAM memory board used in CNC control systems where memory expansion or memory-board replacement is required.

It is described as a DRAM unit, DRAM module 4 MB, and file DRAM module 4 MB.

Several model references connect it with FS 15-B, 16-C, 16-M, 16-T, and some Fanuc 18 controls, while another reference notes fitment to the Main-C CPU board A16B-3200-0060.

Unlike an axis board or I/O board, this module belongs to the control’s memory layer. Its role is tied to storing system memory, files, and programs, which makes exact memory-capacity matching especially important during replacement.

That is also why this model is useful when the existing control needs more memory or when a defective DRAM module has to be replaced with the same capacity and family.

Product Data

Application Scenarios

A20B-2901-0941 is most relevant in CNC memory-board replacement, legacy FANUC control restoration, and memory-capacity upgrades within compatible control families. It fits installations where the system already uses a 4 MB DRAM module and needs to preserve the existing control architecture while restoring storage capacity for programs and system memory.

Why Choose This Product

This model is a strong fit when the installed control already depends on a 4 MB DRAM module and the machine requires the same memory class to keep the original control structure intact.

Because memory boards are matched by both capacity and control family, A20B-2901-0941 is more precise than a generic “Fanuc memory card” description.

Replacement Guide

Before replacing A20B-2901-0941, confirm the exact part number, the 4 MB capacity, and the control family or CPU board already installed.

If the system is based on a 15-B, 16-C, 16-M, 16-T, or compatible 18 control, the existing board label and memory position should be checked before removal.

Where applicable, confirm the installed Main-C CPU board reference as well.

FAQ

Q1. What type of board is A20B-2901-0941?
It is a 4 MB DRAM module, also described as a DRAM unit or file DRAM module for FANUC CNC controls.

Q2. What does this board do in the system?
Its role is to provide memory storage for the control, including system memory and programs.

It belongs to the CNC memory section rather than the axis, I/O, or display section.

Q3. What should be checked when selecting A20B-2901-0941?
Check the full part number, the 4 MB memory capacity, and the control or CPU board family already installed.

References for this model include FS 15-B, 16-C, 16-M, 16-T, some Fanuc 18, and the A16B-3200-0060 Main-C CPU board.

Q4. How should the key specification be understood?
The most important specification is the 4 MB DRAM capacity. For memory boards, capacity is a primary compatibility point because it directly affects how the board fits into the control’s memory architecture.

Q5. How should faults be diagnosed before replacing this board?
Start by separating a memory-board fault from a CPU-board fault or a broader control issue.

If the control’s memory-related behavior is unstable while the system family and installed board position match this 4 MB DRAM module, the DRAM board becomes a stronger candidate.