The most frequent cause is a corrupted FROM (Flash ROM) or SRAM chip. This happens during improper shutdowns, power surges, or when the backup battery dies while the machine is off.
If you determine that the Flash ROM is corrupted and you do not have a backup of the machine parameters and ladder logic, contact the machine tool builder or a FANUC service technician immediately. Attempting a reload without backups can render the machine unusable until re-engineered.
Be prepared to provide the FANUC control model (e.g., Series 31i Model B) and the main board part number (located on a white sticker). Most professional repairs for a frozen boot issue range from $1,500 for a battery/parameter restoration to $8,000+ for board replacement.
Attempting complex repairs without the proper training can cause further damage to the CNC control, leading to more extensive and costly repairs.
If the system files themselves are corrupted, the control will require a fresh installation of the FANUC system software. This process requires specialized system files (FROM data) specific to your machine's exact make, model, and software edition. Contact your machine tool builder (OEM) or a certified FANUC technician to obtain and load these files. Hardware-Level Resolution
Every 3 months, perform a full SRAM backup using one of these methods:
For ongoing support, check out the official Fanuc support page for troubleshooting guides and component manuals.