Fanuc A20B-3900-0074 Memory Module For Fanuc CNC Controllers

The Fanuc A20B-3900-0074 memory module is a DIMM-style memory PCB for Fanuc CNC controllers, providing onboard storage for system data, parameters, and control programs. Compatible with Fanuc 16i, 18i, 20i, and 21i series controllers, it plugs into the CNC master/control board to store CNC parameters and programs, with 4 MB of memory and memory type listed as SRAM/Flash ROM (model variation) in a DIMM-style form factor. It mounts internally on the controller board, weighs approximately 0.03 kg, and operates from 0°C to 40°C with up to 80% non-condensing humidity. Common applications include CNC machining centers, lathes, milling machines, and automated production systems where memory integrity and data retention are essential. Status: Discontinued / legacy component.