Microwave display and lights work, but pressing START produces a beep and no further action; timer does not count down.

Safety: No internal access is required for basic checks.

Steps to restore start function:

• 1. Confirm door closure: Open and firmly close the door. Listen for distinct clicks from the interlock switches.
• 2. Check for lock/demo mode: Refer to the Sage manual to disable any child lock or demo mode that may prevent cooking.
• 3. Try alternative keys: If the START key is unresponsive but other keys work, the membrane keypad may be failing.
• 4. Power reset: Unplug for 5 minutes, then plug back in and test again.

If the START key and door are confirmed good but the unit still will not initiate cooking, the control PCB or door-sense circuit may require professional diagnosis.