On Sat, 26 Jan 2013 09:42:28 -0600, Vic Smith wrote:

As I recall, lateral movement allowed by bad bearing let's
the cable escape the spool. If one side is spooling the cable
differently than the other, you get a cocked door.
You're just making conversation. You know this by now.

You give me more credit than I deserve, but, perhaps I should
apologize for not giving you enough credit in return.

I don't know whether the bearing was bad to start with as it
only fell apart after I started to bang on the 1-inch torsion
bar in an attempt to remove it to untangle the cable mess.

But, assuming the bad bearing was the initial problem, what
you said makes good sense if this is what is going on.

Here's a full-sized closeup of the bad bearing, in situ:
http://www3.picturepush.com/photo/a/...g/12046951.jpg

This is what I think you are suggesting might have happened:
1. Bearing on left side goes bad (see pic above);
2. Spring, in middle, is trying to compress when door goes up
3. Bad bearing (presumably) allows the torsion bar to slide left;
4. That pulls the right (black) drum to the left;
5. That knocks the right side cable off the right cable drum;
6. The right side stops lifting (and stays on the ground);
7. The left side still lifts for a while until the door crooks.

The only problem conceptually I have with that bad-bearing scenario
(which fits the evidence) is that the torsion bar can't slide
all that much to the left even with a bad bearing since the
left cable drum would smack against the bearing end plate.

So, it can only side, oh, about an extra quarter inch (i.e., the
amount the bearing sticks out) or maybe a half inch (at most) to
the left. See closeup of the bad bearing next to a new bearing.
http://www4.picturepush.com/photo/a/...g/12046992.jpg

However, that might be just enough to cause the right side drum
(which 'can' slide to the left) to unspool itself.

I am heading over to her house now, armed with the bearings, to
put it all back together.

As you had mentioned, this is a single-spring system. I considered
converting her to a dual-spring system, but the spring is only two
years old according to the paperwork she showed me, and she
(understandably) balked when I discussed her buying two new springs.

The parts so far were so cheap, I won't ask her for to reimburse
me (the garage door place simply said offhand to give 'em $15
cash for the three bearings & one drum, so I didn't even bother
getting a receipt).

As always, I'll provide an update to be a good nntp netizen.

PS: I enjoy discussing technical things so I appreciate your response.