Machine displays ALARM 10; communication error between main control board and group board or display, some groups may be disabled.

Safety first: Turn OFF and unplug the machine before accessing internal electronics. Static discharge can damage boards; ground yourself before touching connectors.

Steps to resolve ALARM 10:

• Power-cycle: Leave the machine off for 2–3 minutes, then power back on. If ALARM 10 returns, proceed with inspection.
• Inspect communication cables: Remove the top or rear panel to access the main control board and group boards. Locate the low-voltage communication cables (often flat ribbon or multi-core harnesses).
• Reseat connectors: Carefully unplug and replug each communication connector at both ends, ensuring they are fully seated and oriented correctly.
• Check for damage: Look for pinched cables, broken locking tabs, or signs of moisture on the boards. Replace any visibly damaged harnesses.
• Isolate faulty board (advanced): If multiple group boards are present, disconnect them one at a time and power the machine to see if the alarm clears. A single faulty group board can bring down the bus.
• Replace defective board: If a specific group board or the main board is identified as faulty, replace it with an OEM La Marzocco board. Board replacement and firmware configuration are best handled by an authorized technician.