Opener runs briefly then stops; display shows F6; door may not move.

Safety first: Unplug the opener before working on the rail or drive. Support the door if it is partially open.

• 1. Inspect the rail and trolley: Look along the Linear rail for bent sections, loose mounting brackets, or a trolley that is jammed against the stop bolt. Free any binding and straighten minor bends.
• 2. Check chain or belt tension: If the chain/belt is hanging loose or off the sprocket, re-seat it on the sprocket and adjust tension per the manual (usually about 1/4 inch sag at mid-span).
• 3. Examine sprockets and drive gear: Remove the cover and inspect the motor sprocket and internal drive gear for missing teeth or plastic shavings. Replace worn or stripped components.
• 4. Inspect travel limit/encoder assembly: On some Linear models, a limit switch or encoder on the rail or motor shaft provides travel feedback. Ensure the wiring harness is connected and not damaged. If the encoder wheel is broken or the switch is loose, replace the assembly.
• 5. Reset travel limits: After mechanical repair, follow the Linear programming procedure to re-learn open and close limits, then test a full cycle.