Doing It Yourself
A cable under tension from an extension spring will take your fingers off if you handle it wrong, and that's exactly the setup on a lot of Green Hill garage doors - homes here cluster around a 1978 build year, which usually means the older extension-spring-and-pulley style rather than a torsion bar overhead. Those systems store energy in the stretched spring itself, and the cable running off the bottom bracket is under load any time the door is down. If a cable has frayed or popped off the drum, do not try to re-seat it yourself or cut the spring to relieve tension. You can safely unplug the opener and leave the door alone until someone gets there - that's the one DIY step worth doing. Beyond that, this is a job for someone who deals with wound springs daily. We'd rather tell you to wait than have you find out the hard way why this isn't a weekend fix.
The Cost of This Job
We don't post a flat number for cable repair here because the fix depends on what the cable took with it - a clean snap on one side is a different job than a cable that's jumped the drum and chewed up the track or bent a bottom bracket. What we can tell you is that the extension-spring hardware common on Green Hill's older housing stock often means replacing both cables as a pair, even if only one failed, since the other is close behind on wear. Ask for the breakdown before we start work: cable, pulley, drum, and labor, listed separately, not folded into one number.
How Long It Takes
A single cable on one side, no damage to the drum or track, is typically the faster half of a repair visit. If the cable jumped the track and bent the bottom bracket, or if corrosion has pitted the drum - something we see more with the older extension-spring setups that match this area's housing age - the job runs longer because we're replacing hardware, not just cable. We'd rather take the extra time on site than leave a repair that fails again in a few months, especially given the drive back out.
What Can Go Wrong
The biggest risk with a failed cable is what it does on the way down - a door that drops unevenly can rack in the track, bend a panel, or put a sudden shock load on the remaining hardware. On the older extension-spring systems common in Green Hill, a missing or damaged safety cable through the spring itself is the thing we check every time, because without it a broken spring has nothing to stop it from becoming a projectile. Cold snaps in this part of Tennessee can make already-brittle galvanized cable more likely to snap outright rather than fray first, so a door that's been sluggish all winter is worth a look before the cable goes rather than after.
