FANUC Alarm CPMO-064 — MAINCHN is Unknown
Manufacturer wording — MAINCHN is Unknown (G: %d^2)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC CPMO-064 (“MAINCHN is Unknown”): Internal Error: Main Channel is neither JBF nor JF First check: Press RESET.
Updated 2026-09-17 · LogrobotLM reference
Description
Internal Error: Main Channel is neither JBF nor JF
Remedy
Press RESET. If the error is not cleared, document the events that led to the error and call your FANUC or FANUC
Related codes
Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →