The rod along the left side of our miniblinds turns a shaft spanning the length of the housing which pulls-and-releases three pairs of cords tilting the blades, with one roller for each pair. The cords loop over, pass under, and are secured to a tab on the roller with metal ferrules, thusly:
One day, the middle section of all the blades on one miniblind stopped tilting, prompting this discovery:
The correct solution is, of course, to replace the entire miniblind, but our 1955 window frames don’t match up well with contemporary miniblind hardware and I was unwilling to reinvent that particular wheel for this occasion.
So I laid the cords in place, put the broken tab atop them, and held the mess together with a strip of the obligatory Kapton tape:
Easing some epoxy under the tab and soaking the cords atop the tape held everything together in approximately the original layout:
Two days after I reinstalled the miniblind, a second roller broke and was restored by a similar treatment. While I had the thing
on the bench clamped in the bench vise, I preemptively slobbered epoxy on the intact roller in the hope of reinforcing it.
So far, so good!