Microwave display shows H0 or HO; unit does not start and may beep when START is pressed.

Safe to troubleshoot: This is a user setting, not a hardware failure in most cases.

• Disable child lock: On many Ambiano microwaves, press and hold the STOP/CANCEL or LOCK button for 3–5 seconds until the H0/lock icon disappears. Refer to your specific model's manual if this does not work.
• Try alternative sequence: Some models require pressing and holding 0 or a combination like STOP + START for several seconds.
• Check for stuck keys: If the lock will not clear, a stuck keypad button may be causing the control to think the lock command is held. Gently press each button several times to free it.
• Power reset: Unplug the microwave for 5 minutes, then plug back in and attempt to clear the lock again.