We start at the unit, not the door, because most opener calls aren't spring or cable problems at all. We check the logic board for a fault code, test the safety sensors at the base of the track, and look at the limit switches that tell the opener where open and closed actually are. A lot of "dead" openers turn out to be a sensor knocked out of alignment or a capacitor that's given out on the circuit board. If the gear inside the drive head has stripped, we replace that part rather than the whole head, when the part is still available. If it's a chain-drive unit old enough that parts are discontinued, we'll tell you straight rather than chase a part that doesn't exist anymore. We also reprogram remotes and keypads, adjust travel limits so the door seats properly instead of slamming or stopping short, and test the auto-reverse safety function before we leave. That last check isn't optional. A door that doesn't reverse when it hits resistance is a hazard, not a convenience problem.