Fanuc alarm 103: DRAM SUM ERROR
30i/31i/32i system alarm · Fanuc 30i/31i/32i-B
What it means
A checksum error was detected in DRAM during internal processing of the CNC system software on a 30i/31i/32i Model B control. This indicates corrupted memory contents rather than a program error, and it usually appears at power-up or randomly during operation. Fanuc recommends identifying the component named on the third line of the system alarm screen (or in the system alarm log) and replacing it.
Likely causes
- Faulty main board DRAM or memory module
- Marginal 24V DC supply or momentary power dips corrupting memory
- Severe electrical noise near the control
Triage note: Displayed as SYSTEM ALARM on the system alarm screen (no class prefix); third line names the suspect hardware.
Need the part urgently?
Send us alarm 103 with your machine details — typical RFQ turnaround is 24–48h.