Marantec 118798 Trolley Replacement Kit for sale online | eBay
Is It Time to Replace Your Garage Door Opener?
Garage Door Won't Open or Close: Reasons and Solutions
What do you do when a garage door's emergency cord was pulled while in the up position? - Quora
365 Overhead Garage Door & Gate - Red release cord may get pulled which disengages the trolley: if unit runs but the black trolley doesn't move, check to re-engage the cord first.
Garage Door Emergency Release | Premier Overhead Co. in Killeen