Opener runs briefly then stops, motor hums or stalls, display shows code 5.

Safety first: Unplug the opener before removing covers. If you smell burning or see smoke, leave power off and call a technician.

• Check door movement manually: Pull the emergency release and move the door by hand. If it is hard to move, the problem is with the door, not the opener. Have springs and hardware serviced.
• Inspect drive system: For chain/belt drive Merlin units, remove the light cover and motor cover. Check the drive sprocket, belt/chain tension, and trolley carriage for broken teeth or binding. Clear any obstructions on the rail.
• Check for jammed trolley: Ensure the trolley is not jammed against the stop bolt. Manually move it a short distance away from the stop and retry.
• Examine capacitor: Many Merlin AC motor models use a start/run capacitor mounted near the motor. Look for bulging, leaking, or burnt smell. A failed capacitor should be replaced with the exact Merlin‑specified µF rating and voltage.
• Test after cooling: Allow the opener to cool for 15–20 minutes, then try a single cycle. If the code returns immediately and the motor only hums, the motor or capacitor is likely faulty and requires replacement.