|
| Place of Origin | JAPAN |
| Brand Name | FANUC |
| Certification | CE ROHS |
| Model Number | A20B-3900-0164 |
The FANUC A20B-3900-0164 is a 32MB FROM / 2MB SRAM module in the A20B-3900 family.
It is best understood as a control-memory board used where the original storage structure of the CNC must be preserved with the correct module rather than substituted with a loosely similar card.
In service work, a module in this class matters because memory replacement is rarely just a matter of physical fit.
The capacity combination is part of the control’s intended configuration, so matching the exact part number helps maintain the original board-level memory layout and reduces unnecessary risk during repair.
| Parameter | Value |
|---|---|
| Part Number | A20B-3900-0164 |
| Brand | FANUC |
| Product Type | Memory Module / PC Board |
| Module Type | FROM / SRAM Module |
| FROM Capacity | 32MB |
| SRAM Capacity | 2MB |
| Product Family | A20B-3900 series |
| Typical Use | CNC control memory replacement |
The A20B-3900-0164 is well suited to control-memory replacement, board-level CNC restoration, and spare-parts support for FANUC systems that still rely on the original A20B-3900 memory architecture.
It is especially useful when the control hardware remains serviceable and the machine only needs the correct memory module to return to stable operation.
It also fits repair inventory, exchange programs, and legacy machine support where a direct module replacement is more practical than changing the wider control platform.
In real maintenance environments, this is the kind of board that helps keep older but productive equipment in service.
Q1: What is the A20B-3900-0164 used for in a FANUC system?
The A20B-3900-0164 is a FROM / SRAM memory module with 32MB FROM and 2MB SRAM.
In practical terms, it belongs to the control-memory layer rather than the amplifier, display, or operator-panel side of the system.
A module in this role is used when the controller needs to retain the original internal memory structure and cannot simply accept any board from the same family.
Q2: Why is exact part-number matching so important for this module?
Memory boards in the A20B-3900 family may look physically similar while still using different FROM and SRAM combinations.
With the A20B-3900-0164, the 32MB / 2MB configuration is part of the board’s identity, so the part number is not just a catalog label. In service work, that matters because the control expects a specific memory layout, and using a different module can create compatibility problems even when the connector format appears correct.
Q3: Does replacing this module involve only hardware, or does data management matter too?
Data handling matters. One service listing for this model specifically warns that data will be lost during the replacement process and needs to be restored.
In practice, that means technicians should treat this as both a hardware replacement and a recovery task.
Before removal, it is wise to confirm what data is stored in the control, what backup procedure is available, and whether the machine builder added any application-specific data that must be restored after installation.
Q4: Is this module mainly relevant to new systems or to repair work?
It is much more relevant to repair, restoration, and long-life support than to new machine design.
Current market listings present it as a replacement memory module, and service suppliers position it as part of ongoing support for installed FANUC hardware.
In industrial terms, that usually means the control is still worth keeping in service, and replacing the correct memory module is more practical than redesigning the wider platform.
Q5: What should technicians check before and after installing A20B-3900-0164?
Before installation, confirm the exact installed part number, inspect the connector area, and verify that the fault really belongs to the memory path rather than to the main PCB or a separate software issue.
Because this module is tied to stored memory, a stable board swap depends on both electrical fit and proper data handling.
After installation, the control should be checked for normal startup, correct memory recognition, and successful restoration of any required data. The service note about data loss makes post-installation verification especially important for this model.
Contact Us at Any Time
