A door that won't open evenly, dropping lower on one side as it travels, is the most common sign. Sometimes you'll see the cable itself - frayed strands near the bottom bracket, or a cable that's come loose off the drum entirely and left slack where there should be tension. On a two-car door, a single snapped cable usually means the door jams at an angle a few inches up, stuck crooked in the track. On some of the lighter steel doors common to this build era, you may also notice the bottom corner bracket bent or pulled where the cable let go under load. None of this is a DIY fix - a cable under tension that lets go while someone's hands are near the bracket is how fingers get hurt, and that's the one thing we're always direct about with callers.