Garage door cable came loose

[Alchase]

I had a weird situation a couple days ago. I had my single bay garage door (of a three bay garage) open for a few hours. I rarely open this door except to get my mower out. When I went to close the door it stopped 2/3ds the way down.
I notices the cable on the right side had come off the spool and had wrapped itself around the bottom corner of the door. I was able to disconnect the cable from the door, and was getting ready to call a Garage Door guy, when I decided to take a close look at the other side. Left side was good nice and tight on the spool. So I took a chance and re-spooled the right cable. When I was done, it looked nice and tight. I ran the door up and down a few times and so far seems to be working fine.

My question, what would cause the cable to come loose like this?
Is there anything I should be looking for?

 

[slimpickins]

Hi Alchase,
I assume we're talking about a standard torsion spring?
Since you say you don't open the door very often, did the door stick to the ground for a second and then pop up? if it did, the cable can jump the spool and cause various problems, including the one you describe.

 

[Alchase]

Thanks for your reply!
It did not stick to the floor, but when I first opened it, it got stuck when the "sliding lock bar?" had somehow slid into the locked position while opening and got caught on a seem in the track. I had to knock the bar back out and straighten part of the track.
I assume this could cause a similar situation as you describe?

Thanks for your input!

 

[Hot Rod Grampa]

Yes your door got racked when one side stopped moving and the other did not. The cable has a memory and wants to uncoil so the momentary loss of tension would cause it jump off the drum. You must have fiddled with the cable to get it back on or did you loosen the drum? Either way, it's working again. Check that the tension is about equal on both cables. Pluck them like a guitar string and it will resonate. They will sound similar.

 

[Alchase]

I was worried about the tension.
I disconnected the cable, then opened the door all the way up so the left side was almost completely on the drum. Then I wrapped the loose cable on as tight as I could back on the drum.
Not knowing much about garage doors, I was concerned this was just a temporary fix, or a sign of something worse.