USED Fanuc A20B-3900-0166 Memory Card Circuit Board A20B39000166 Controller 1PC A2OB-39OO-O166

FANUC A20B-3900-0166 Memory Module

Overview

The A20B-3900-0166 is a FANUC memory module identified in public product listings as 64 MEG FROM / 1 MEG SRAM MODULE.

It belongs to the A20B-3900 series and is consistently classified as a board-level memory product rather than a CPU board or I/O PCB.

This module is used where the installed control hardware depends on a specific memory configuration inside the FANUC system. In practical service work, memory modules are not interchangeable by appearance alone, because the storage type and capacity are part of the machine’s original control configuration.

For that reason, exact identification matters more here than broad family similarity.

Technical Data

Application Value

This module is suited to FANUC control systems that require the original 64 MB FROM and 1 MB SRAM memory configuration.

It is especially relevant in service and replacement work where the installed control is already built around this exact storage profile and the objective is to preserve the machine’s original board-level memory structure.

Unlike general-purpose controller boards, memory modules are closely tied to the control’s installed data and storage arrangement.

Using the correct module helps maintain the intended memory class inside the original hardware environment.

Selection Notes

The most important checks are the exact part number, the A20B-3900 family, and the stated memory profile 64 MEG FROM / 1 MEG SRAM. These points define whether the module matches the original system hardware.

FAQ

Q1: What kind of module is A20B-3900-0166?
It is a FANUC memory module. Public industrial parts sources consistently describe it as a 64 MEG FROM / 1 MEG SRAM MODULE, which makes it a storage-related control component rather than a CPU main board or a process I/O board.

Q2: Why is the exact memory description important?
Because the published description is the defining specification of this module. When a board is identified by a precise combination such as 64 MEG FROM / 1 MEG SRAM, that memory structure is part of the original hardware requirement.

Matching that description is essential when replacing the module in an installed control system.

Q3: Is this a main PCB or a dedicated memory board?
The public descriptions identify it as a memory module, not as a main CPU PCB. That matters in replacement work because different board types in the same control family perform very different functions, and the memory-module role should be preserved exactly.

Q4: What kind of replacement work is this module usually used for?
It is typically used in board-level maintenance and memory-module replacement for FANUC control systems already built around this exact configuration.

Public supplier listings present it as a dedicated spare item where the original memory class must be retained.

Q5: What should be checked before ordering?
Check the installed part number, confirm that the machine requires A20B-3900-0166, and verify that the original module description is 64 MEG FROM / 1 MEG SRAM.

Those are the key compatibility points for this product.