Cable-style window regulator repair

[Brynjminjones]

The driver's window on our 1991 no longer travels all the way up, leaving about 2 inches at the top when it starts clicking.
The previous owner has moved the entire mechanism up inside the door to compensate, so it now effectively goes all the way up but not all the way down.

I'd like to fix this, as it makes it very uncomfortable to put my arm out the window!

Is it possible to repair this style regulator or does it need the whole assembly replacing?

[Brynjminjones]

A quick follow-up. I discovered that it is in fact possible to replace the cable in the regulator, although I'm not sure if it's possible to buy them separately.

I accidentally bought a passenger side one, when what I needed was a driver's side. I stole parts from both to get one that worked properly.

What I did was:

-Remove regulator from Jeep.
-Apply 12V to motor in order to wind to the end of the cable. There's nothing to stop it going all the way so it will spit the cable out completely.
-The brackets that bolt to the window were different from left/right side on mine so needed swapping.
-The bracket simply threads into the end of the cable. It might have a plastic coating on it to disguise this, but twisting the cable relative to the bracket with some vice grips simply unthreaded the bracket.
-Swapped the correct bracket onto the good cable.
-Threaded new cable into correct regulator, then apply 12V in opposite polarity to get motor to wind the cable in.

The reason my regulator wasn't working turned out to be because the cable had started to not engage with the motor. This caused it to grind, which eventually wore away the metal of the cable.
Based on what I've seen now, I would say that the cable from the regulator in an XJ would probably be a suitable replacement which is much easier to find.