|
| Place of Origin | JAPAN |
| Brand Name | FANUC |
| Certification | CE ROHS |
| Model Number | A20B-3900-0052 |
The FANUC A20B-3900-0052 is a 512KB SRAM module used in 16i / 18i / 20i / 21i control systems.
It is described as a DIMM memory board that installs on the i-Series master board, and some listings also extend its fit to 15i and Power Mate i D/H contexts.
That places it in the controller memory structure rather than in the amplifier or front-panel section.
From a service perspective, this board is a very typical example of a part that looks simple but performs a very specific job.
The 512KB SRAM value is part of the module identity, so the practical task is not just “replace a bad memory board,” but replace it with the correct SRAM configuration expected by the installed FANUC control.
| Parameter | Value |
|---|---|
| Part Number | A20B-3900-0052 |
| Brand | FANUC |
| Product Type | SRAM Module |
| Memory Capacity | 512KB |
| Module Style | DIMM memory module |
| Commonly Listed Controls | 16i / 18i / 20i / 21i |
| Additional Listed Fit | 15i / Power Mate i D/H |
| Installation Context | i-Series master board |
On a professional product page, A20B-3900-0052 works best when described as a master-board SRAM module rather than as a generic “PCB board.”
That phrasing aligns with how technicians actually search for it and helps the page communicate a clear technical role: it is a retained-memory board for older FANUC control platforms.
It also helps differentiate the board from A20B-3900-0053, which is another SRAM module in the same family but with a different capacity.
That distinction is valuable for search visibility and also for real repair work, because the two modules should not be treated as the same replacement part.
Q1: What is A20B-3900-0052 used for?
It is used as a 512KB SRAM module on the master board of FANUC i-Series controls such as 16i, 18i, 20i, and 21i.
Its role is internal control memory, not drive control, spindle power, or panel operation.
Q2: Is this the same as A20B-3900-0053?
No. The two boards are related SRAM modules, but A20B-3900-0052 is 512KB, while A20B-3900-0053 is 256KB.
That difference matters in actual control compatibility, so they should not be treated as interchangeable.
Q3: Which controls is this module commonly linked with?
It is most commonly listed for 16i / 18i / 20i / 21i systems, and some seller data also mentions 15i and Power Mate i D/H.
In practical terms, that means it is part of the older FANUC memory-board ecosystem and should be matched to the installed control rather than assumed from family name alone.
Q4: Where does it install inside the control?
Listings describe it as a DIMM-style module on the i-Series master board. For technicians, that means replacement should include checking the socket condition, connector cleanliness, and secure seating on the main board, not just swapping the module itself.
Q5: What should technicians verify before replacing A20B-3900-0052?
They should verify the installed board number, confirm the required SRAM capacity, and make sure the memory fault really belongs to the module rather than to the master board or another control issue.
After installation, the control should be tested for normal startup and memory-related stability.
The final checks are engineering best practice based on the board’s role as a master-board SRAM module.
Contact Us at Any Time
