fix garage door opener

Houston TX

Description

Liftmaster 1/3 HP needs diagnosis. With the door closed and latch disconnected (red rope pulled down), the trolley travels about half inch towards the opener at a time and the opener light bulb flashes once. Continuing to pressing the opener wall button a few more times keeps moving the trolley quarter/half inch at a time. After about two inches of travel the trolley reveres back towards the garage opening. The safety sensors are checked clear. See video here - Put cost to repair/diagnose in bid.