There's a short list of things worth doing yourself on a commercial door and a much longer list that isn't. Cleaning and lubricating rollers and hinges, checking that the photo eyes are aligned and unobstructed, and visually checking cables for fraying are all fine to do without us. Adjusting torsion spring tension, replacing cables under load, or working on a chain hoist while the door is anything but fully down and disconnected is not something to take on, commercial or residential. On a door this size, the stored energy in a torsion spring or a loaded chain hoist can put someone in the hospital, and on an older 1970s-era unit the spring may already be under uneven tension from decades of wear that isn't obvious just looking at it. If the door won't close square, is making a new noise, or the safety eyes have started failing intermittently, that's a call, not a weekend project.