LiftMaster opener unresponsive; DOWN arrow LED is solid ON and UP arrow LED is OFF.

Safety: Unplug the opener before inspection. Do not repeatedly try to run a stalled motor; it can overheat and cause damage.

• Check door balance: Pull the emergency release and move the door by hand. If the door is very heavy or stuck, have the door hardware repaired before further opener testing.
• Inspect gear and sprocket: Remove the opener cover. Check the main drive gear (usually white plastic) and sprocket. Look for melted plastic, missing teeth, or metal shavings that could jam the motor.
• Allow motor to cool: If the opener was run repeatedly, allow 20–30 minutes for the motor thermal protector to reset, then test again.
• Check motor capacitor: Inspect the motor start capacitor for bulging, leaking, or burnt smell. A failed capacitor can cause high current draw and overload.
• Replace failed components: If the gear is damaged, install a LiftMaster gear and sprocket kit. If the motor hums and trips again, replace the motor capacitor or the motor assembly as required.

Warning: If you smell burning or see smoke, discontinue use and have a professional inspect the opener.