A20B-3900-0222 Fanuc PCB Board A20B39000222 A2OB-39OO-O222

FANUC A20B-3900-0222

16MB FROM / 3MB SRAM Module for FANUC CNC Memory Service

Product Overview

The FANUC A20B-3900-0222 is a 16MB FROM / 3MB SRAM module in the A20B-3900 product series.

It is sold as a control-memory component rather than a general PCB, and at least one supplier specifically associates it with 30iA, 31iA, 32iA, and 21iB control applications.

This model stands out because of its 3MB SRAM configuration.

In practice, that makes exact matching more important than it might seem at first glance, since another module from the same family may share a similar appearance while using a different SRAM size and serving a different memory layout. 

The same seller note also says that after replacement the customer must reload FROM files, parameters, and programs, which makes this module both a hardware part and a data-sensitive service item.

Parameter Table

Applications

The A20B-3900-0222 is best suited to memory replacement in 30iA, 31iA, 32iA, and 21iB controls, especially where the machine still depends on the original memory structure and needs the correct FROM/SRAM module to return to service.

It is a strong fit for control restoration, repair stock, and board exchange work where replacing the exact memory module is more practical than changing the wider platform.

It also works well in service departments that handle data-sensitive memory replacement.

Since replacement listings specifically mention reloading files, parameters, and programs, this module is especially relevant in shops that follow a disciplined backup-and-restore process during repair.

FAQ

Q1: What is A20B-3900-0222 used for?
It is a 16MB FROM / 3MB SRAM control-memory module used in FANUC systems, with sellers specifically listing it for 30iA, 31iA, 32iA, and 21iB controls.

Q2: Why is the 3MB SRAM value important?
Because SRAM capacity is part of the module’s identity and affects how it fits into the control’s original memory structure.

A different SRAM size may indicate a different module even within the same board family.

Q3: Does anything need to be restored after replacement?
Yes. Seller notes for this module say that FROM files, parameters, and programs must be reloaded after replacement, so it should be treated as both a hardware and a data-recovery task.

Q4: Is this a generic A20B-3900 memory card?
No. It is a specific capacity variant within the A20B-3900 family. That is why the safest replacement method is to match the exact module number rather than only the series name.

Q5: Where is this module most useful?
It is most useful in repair work on FANUC controls that still have production value and need the correct memory hardware to remain operational without a full control retrofit.